This challenge is intended to be solved by using, manipulating, or creating shapes or other geometric structures.

learn more… | top users | synonyms

3
votes
0answers
78 views

Decompose the domain

In scientific computing, it is often desirable to decompose some large domain into smaller "subdomains", then parallelize the computation by performing the work on each subdomain in parallel and the ...
16
votes
9answers
937 views

g​o​l​f​ ​a​t​a​n​2

Sometimes it really is a struggle to convert cartesian coordinates (x,y) to polar coordinates (r,phi). While you can calculate r = sqrt(x^2+y^2) quite easily, you often need some distinction of cases ...
22
votes
4answers
592 views

Rotate a hypercube

Introduction A hypercube/tesseract is the 4 dimensional equivalent of a normal cube. It's made by taking a cube net, extending it to the 3rd dimension, then – using the 4th dimension – folding it ...
2
votes
0answers
50 views

Does the triangle contain the origin? [duplicate]

Challenge description On a Cartesian plane, a triangle can be described as a set of three points, each point being one of the triangle's vertices. For instance, coordinates (2, 1), (6, 8), (-7, 3) ...
32
votes
4answers
4k views

The happy Ender problem

The happy ending problem (actually a theorem) states that Any set of five points in the plane in general position has a subset of four points that form the vertices of a convex quadrilateral. ...
-12
votes
9answers
197 views

Find the circumference! [closed]

Challenge Well, find the circumference of any circle. You'll be using the formula 2*pi*radius or pi*diameter. Rules You will take an input, r or d, as command line argument or stdin. Your program ...
9
votes
8answers
2k views

Do these squares overlap?

Given the coordinates of the upper left corners of two squares and their side lengths, determine whether the squares overlap. A square includes the top and left lines, but not the bottom and right ...
9
votes
4answers
478 views

Calculate the Fermat Point of a Triangle

This is somewhat similar to The centers of a triangle, but with a different point. The Fermat Point is the point P in triangle ABC such that the value of AP + BP + CP is minimized. There are two cases:...
26
votes
1answer
370 views

Gasket Weaving - draw a Sierpiński knot

Given an integer N >= 2, produce an image showing a Sierpiński knot of degree N. For example, here are knots of degree 2, 3, 4 and 5: Click on the images to view full size (the higher the ...
-8
votes
18answers
260 views

Find the remaining side of the tangential quadrilateral!

(Taken from https://en.wikipedia.org/wiki/File:Tangential_quadrilateral.svg) A tangential quadrilateral (see example above) is a quadrilateral in which a circle can be inscribed. Your task is to ...
5
votes
1answer
216 views

Tiling by substitution

EDIT: The incorrect A rhomb substitution has been fixed. Apologies to anoyone who had started working on a solution. Consider the following substitutions, where the substituted rhomb(us) is scaled up ...
4
votes
15answers
290 views

Counting triangles with integer perimeter

Mary has given John two sticks of lengths a and b respectively, where a and b are positive integers. John is very curious. He would like to know how many triangles with integer perimeter can be ...
9
votes
3answers
569 views

Draw a simple cube

We don't have a single challenge about drawing a real 3 dimensional cube, so here it goes: Challenge Your task is to draw a rotated, cube with perspective. It can be in a separate window or as an ...
17
votes
1answer
225 views

Symme-Try This Triangle Trial

A string whose length is a positive triangular number (1, 3, 6, 10, 15...) can be arranged into an "equilateral text triangle" by adding some spaces and newlines (and keeping it in the same reading ...
7
votes
17answers
983 views

Form tiles in a rectangular ring

Given the input tilesX and tilesY create a method that would make a rectangular ring from the tiles. The function must order the tiles in a ring like this: tilesX and tilesY are always positive ...
9
votes
2answers
339 views

Find the area of a polygon

Given consecutive side lengths s1, s2, s3... s_n of an n-gon inscribed in a circle, find its area. You may assume that the polygon exists. In addition, the polygon will be convex and not self-...
7
votes
3answers
299 views

How can I shorten this python code analyzing a 3d grid?

My Python 3 function golf(...) should take a list of lists of lists of strings representing a solid cube and return whether there are any places in which two equal strings are directly next to each ...
42
votes
9answers
5k views

Build a triangle without any triangles

As a little kid, I liked to play with these toys a lot: They probably intended for these to be used for art, but I always used them for math! Fractals, patterns, etc. One time, I was given this ...
4
votes
1answer
345 views

Need help golfing Python 3 code to calculate volume & surface of spheroids in <150 bytes

I want to write a function golf(C, A) that takes the height (C = 2*c) and the width (A = 2*a) of an oblate (left image) or prolate (right image) spheroid or a sphere as parameters and returns the ...
20
votes
9answers
1k views

Rectangle Detection

Write a program or function that takes in a multiline string of 0's and 1's. No other characters will be in the string and the string will always be rectangular (all lines will have same number of ...
16
votes
2answers
501 views

Draw a random hexa-glyph

The above image is called a hexa-glyph. Hexa-glyphs are some cool patterns I made up while doodling during my DiffEq class. Here's how you make one: Consider the following set of points, shaped ...
14
votes
5answers
201 views

Identify arborally satisfied point sets

An arborally satisfied point set is a 2D set of points such that, for any axis-aligned rectangle that can be formed using two points in the set as opposite corners, that rectangle contains or touches ...
8
votes
2answers
149 views

Count rectangle intersections

The Challenge Given an arbitrary amount of rectangles, output the total count of intersections of those when drawn in a 2D plane. An intersection here is defined as a point P which is crossed by two ...
14
votes
4answers
274 views

How far from the exterior?

Take a 2D region of space divided into axis aligned unit square elements with their centers aligned at integer intervals. An edge is said to be internal if it is shared by two elements, otherwise it ...
11
votes
3answers
271 views

Trilaterate your position

Introduction Imagine you are on a two dimensional cartesian plane and want to determine your position on it. You know 3 points on that plane and your distance to each of them. While it is always ...
28
votes
2answers
264 views

Addition on Elliptic Curves

Addition on Elliptic Curves Disclaimer: This does not do any justice on the rich topic of elliptic curves. It is simplified a lot. As elliptic curves recently got a lot of media attention in the ...
8
votes
7answers
290 views

Hexagon-In or Hexagon-Out?

There is a great story to tell about regular hexagons found for example in honeycombs. But this busy bee needs your help in telling him which point is inside or outside his honeypot. So, given a ...
18
votes
12answers
2k views

Calculate the volume of an object

You can determine the volume of objects based on a given set of dimensions: The volume of a sphere can be determined using a single number, the radius (r) The volume of a cylinder can be determined ...
17
votes
2answers
535 views

Cities: Sightlines

I'm at position (0, 0) of an infinite two-dimensional city, which is perfectly divided into blocks centered at each lattice point, some of which contain buildings. A building at a certain point (x, y) ...
18
votes
3answers
400 views

Text on a circle

Write a program or function that prints an input string around the discrete circle that has the minimum possible radius. For example, for input This is an example, your program should output: a si ...
8
votes
1answer
176 views

Extend the line

Task Given an image with a line on it, produce or display an image with the line extended the the line to the edge of image. The line is black and the background is white. The image size is 100x100 ...
15
votes
3answers
357 views

Where does the spaceship go?

Based on an idea suggested by Zgarb. A spaceship is moving around a regular 3D grid. The cells of the grid are indexed with integers in a right-handed coordinate system, xyz. The spaceship starts at ...
6
votes
1answer
120 views

Test if a point is in an Icosahedron

Take as input 3 floating point numbers, which represent the x, y, z coordinates of a point. Return a truthy or falsey value indicating whether the point is inside the regular icosahedron centred at ...
13
votes
4answers
233 views

Compute the winding number

The winding number is the integer number of net counterclockwise revolutions an observer must have made to follow a given closed path. Note that any clockwise revolutions count negative towards the ...
19
votes
15answers
2k views

Hypercube elements

Write a function or program that outputs the number of each type of element (vertex, edge, face, etc.) of an N-dimensional hypercube. As an example, the 3 dimensional cube has 1 cell (i.e. 1 3-...
20
votes
28answers
2k views

Distance between two points in n-dimensional space

Here is another simple one: The Challenge Given two points in an n-dimensional space, output the distance between them, also called the Euclidean distance. The coordinates will be rational numbers;...
3
votes
4answers
173 views

Find our neighbors

You live in a rectangular neighborhood which is completely partitioned into N rectangular plots, i.e. there are no gaps or overlaps. Plots do not necessarily have the same width/height as other plots. ...
21
votes
15answers
3k views

Geometry is So Fun

Everybody loves geometry. So why don't we try and code golf it? This challenge involves taking in letters and numbers and making shapes depending on it. The Input The input will be in the form of (...
7
votes
5answers
742 views

Hypercube sides

Your goal is to output all the "sides" (corners, edges, faces, etc.) of an N-dimensional unit hypercube, where N is non-negative. A "side" is defined as any (N-M)-dimension surface embedded in N-...
1
vote
2answers
198 views

Find the line guaranteed by Sylvester-Gallai

The Sylvester-Gallai theorem says: Suppose you have a finite list of points in the plane. Suppose further that not all of those points are collinear (lie in a single line). Then there is some line ...
35
votes
14answers
4k views

Toilet Paper Mysteries

Today you need to solve a very practical problem: How many loops do you need to have a certain number of sheets on your toilet paper roll? Let's look at some facts: The diameter of a bare toilet ...
20
votes
3answers
463 views

Putting square pegs into square holes

I was intrigued by the design of this graphic from the New York Times, in which each US state is represented by a square in a grid. I wondered whether they placed the squares by hand or actually found ...
16
votes
1answer
168 views

Finding Exclusive Area in Circle Intersections

Here's a deceptively challenging geometry puzzle for you! Given a circle A, and n other circles B[n], find the total area contained within A that is not within any circle of B. Your code should be ...
11
votes
0answers
172 views

Lego Gear Train

Inspired by the Lego gear ratios challenge by Keith Randall. I, too, plan on building a giant lego robot that will eventually be able to destroy the other robots in the never-before-mentioned ...
9
votes
3answers
456 views

Draw a Christmas Star / Stellated Dodecahedron

Paper stars are a big thing in my family at christmas, so I thought a virtual one would be cool. Below is an image of a regular dodecahedron (from https://en.wikipedia.org/wiki/Dodecahedron, ...
30
votes
16answers
2k views

How much present did you get for Christmas?

Yes, how much, not how many... As we all know, a large present is far better than a small one. Therefore, the value of the presents should always be measured in total volume, not number of presents, ...
16
votes
2answers
320 views

Playing Billiards

In this code golf, you will have to determine the direction of the shortest shot that hits exactly n cushions before falling into a pocket. The billiard table is a 6 pocket pool table with the ...
3
votes
3answers
122 views

Most logical rectangle formula from numbers [duplicate]

Introduction The task is simple. When given a number, output the most logical rectangle. To explain what a logical rectangle is, I provided some examples: Input: 24. All possible rectangles have ...
16
votes
3answers
486 views

Rolling the Dice

Rolling the Dice So, I was rolling dice a while ago and thought of a challenge. Given the cube with a net taken from input and a list of moves, find the square on the bottom at the end. I will ...
10
votes
4answers
337 views

Point in convex hull (2D)

Background The convex hull of a finite number of points is the smallest convex polygon that contains all of the points, either as vertices or on the interior. For more information, see this question ...