# Questions tagged [geometry]

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

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10answers
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### Draw the South Korean flag

When I stumbled upon this question I remembered that I had also once seen precise rules for the construction of the South Korean flag. And this is quite a different construction. Source: Wikipedia ...
79answers
23k views

### Draw the national flag of Iceland

This year's UEFA Euro 2016 is over and besides a couple of negative headlines there has been a very positive surprise as well – the Iceland national football team. Let's draw their national flag. ...
5answers
3k views

### Block Building Bot Flocks!

The contest is over! Intro This is an interactive king-of-the-hill contest where the controller is fully contained in a Stack Snippet at the bottom of the question. The controller automatically ...
6answers
7k views

### Let's draw the flag of Nepal

Nepal’s flag (Wikipedia, Numberphile) looks very different from any other. It also has specific drawing instructions (included in the Wikipedia article). I want you guys to make a program which will ...
84answers
20k views

### Draw the national flag of France

There have been many other flag challenges posted but not one for the national flag of France. This week seems like an appropriate time. Produce this flag in the fewest bytes possible: The image ...
16answers
10k views

### Draw the € sign

The goal is to output or display an image with an € (euro) sign according to the following specs (ignoring the border of the sign). Source: http://en.wikipedia.org/wiki/File:Euro_Construction.svg ...
22answers
8k views

### Check if point lies inside triangle

Your goal is to determine whether a given 2D point X lies within the area of the triangle with given vertices A,B,C. Write a function that takes in the coordinates of the test point X and the three ...
8answers
2k views

### Dennis, Doorknob, Martin Büttner, Chris Jester-Young - Pizzeria!

Programming Puzzles & Code Golf is about to get a new moderator, Dennis! This challenge is a tribute to him and our other active (or recently active) moderators: Doorknob, Martin Büttner, and ...
3answers
3k views

### Area of a Self-Intersecting Polygon

Consider a potentially self-intersecting polygon, defined by a list of vertices in 2D space. E.g. ...
41answers
5k views

### Draw an ASCII Rectangle

Given two integers as input in an array, draw a rectangle, using the first integer as width and second as height. Or, if your language supports it, the two integers can be given as separate inputs. ...
3answers
1k views

### 2D Collision Detection

This challenge is based on actual collision detection I had to write for a simple game recently. Write a program or function which, given two objects, returns a truthy or falsy value depending on ...
3answers
1k views

### The centers of a triangle

Circles and squares have a single, definite center point. However, the notion of the center of a triangle has long been discussed. Four different centers were known to the Ancient Greeks: Incenter: ...
2answers
637 views

### Simple Geometric problem

This problem (see below) has been given as a High School Programming League code golf challenge. The shortest codes submitted during the contest were: 177 bytes in Ruby, 212 bytes in Python 2.5, 265 ...
4answers
4k views

### Find the Convex Hull of a set of 2D points

When you hammer a set of nails into a wooden board and wrap a rubber band around them, you get a Convex Hull. Your mission, should you decide to accept it, is to find the Convex Hull of a given set ...
38answers
5k 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; ...
6answers
902 views

### A cube of text ݀

Last time you made a square of text, but now, can you make a cube of text? The Challenge Given a string, output the string in the form of a cube. You can assume the string will always have 2 chars ...
19answers
3k views

### Chebyshev Rotation

Consider a regular grid, where each cell has integer coordinates. We can group the cells into (square-shaped) "rings" where the cells in each ring have the same Chebyshev distance (or chessboard ...
9answers
2k views

### I really wanted a rhombus, but all I got was this stupid rectangle

Given only a straightedge and compass, inscribe a rhombus inside the given rectangle, sharing two opposite points. Input Input is the dimensions of the rectangle. In the example shown, that would be ...
4answers
1k views

### Three-pointer! But what kind?

From http://en.wikipedia.org/wiki/Triangle: Write a program that takes three 2d coordinate tuples (Cartesian), and classifies what shape these three points describe. In almost all cases these points ...
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. The ...
12answers
3k views

### What is the area of this polygon?

Calculate the area of a polygon. Inspired by this shoelace algorithm video. Task Your job is to create a program or function that calculates the area of a polygon. Program or function is defined ...
10answers
2k views

### Generate a right triangle

In this challenge, you must take two numbers (separated by a space) as input and output an ASCII right triangle, made up of xs. The first number will be the width ...
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-...
3answers
539 views

### Regular Polygrams

Given the number of vertices n ≥ 3 and the "step size" 1 ≤ m < n/2 (indicating the distance between two connected vertices), ...
3answers
474 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 ...
7answers
544 views

### Intersection of Two Lines

Given equation of two lines in the format Ax+By=C, determine their intersection point. If they are parallel print 'parallel' without quotes. For input/output format refer sample input/output. ...
5answers
791 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-...
8answers
31k views

### Draw an Image as a Voronoi Map

Credits to Calvin's Hobbies for nudging my challenge idea in the right direction. Consider a set of points in the plane, which we will call sites, and associate a colour with each site. Now you can ...
10answers
10k views

### Little Chandler is sad. Draw him a cloud to cheer him up

Little Chandler is sad. Draw him a cloud to cheer him up. Note: Drawing a cloud won't actually cheer him up. A circle can be defined as a 3-tuple (x,y,r) where <...
21answers
6k views

### Random point on a sphere

The Challenge Write a program or function that takes no input and outputs a vector of length $1$ in a theoretically uniform random direction. This is equivalent to a random point on the sphere ...
4answers
847 views

### Smallest region of the plane that contains all free n-ominoes

On Math Stack Exchange, I asked a question about the smallest region that can contain all free n-ominos. I'd like to add this sequence to the On-Line Encyclopedia of Integer Sequences once I have ...
3answers
3k views

### Fill the Screen with Wang Tiles

It has been proven that the following 13 square Wang tiles always tile the plane aperiodically. This means that when the squares are arranged in a grid with all neighboring sides the same color, a ...
12answers
1k views

### Embedded Diamonds!

No, not this. And not this either. This question is nothing like those Write the shortest code to print/return the following output: ...
21answers
7k views

### Angle between the hands on a clock [duplicate]

Given the time in 24 hour format (2359 = 11:59pm) return the angle between the minute and hour hands on a standard clock (on the ...
2answers
1k 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 ...
8answers
870 views

### Is this quadrilateral cyclic?

In mathematics, a cyclic quadrilateral is one whose vertices all lie on the same circle. In other words, every vertex is on the circumcircle of the other three. For more information, see the MathWorld ...
2answers
1k views

### Construct n-gons with a ruler and compass

The task is to draw a regular polygon of n sides using only a compass and an unmarked ruler. Input (n) is one of the following 10 numbers: 3, 4, 5, 6, 8, 10, 12, 15, 16, 17. Method: Because you only ...
24answers
5k views

### Count the number of triangles

Given a list of positive integers, find the number of triangles we can form such that their side lengths are represented by three distinct entries of the input list. (Inspiration comes from CR.) ...
4answers
714 views

### Triangular battleships (A computational geometry problem)

You are the captain of a battleship. The engineering department's been cutting corners with designs this year, so the ship you're on takes the shape of a simple triangle. You walk out onto the deck ...
3answers
53k views

### Polygon prefixes

Polygons are named after the number of sides that they have. A pentagon has 5 sides, an octagon has 8 sides. But how are they named? What's the name for a 248-sided polygon? All polygons are suffixed ...
15answers
2k views

### Triangular Lattice Points close to the Origin

Background A triangular grid is a grid formed by tiling the plane regularly with equilateral triangles of side length 1. The picture below is an example of a triangular grid. A triangular lattice ...
20answers
3k 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, ...
6answers
2k views

### Two dozen kissing number approximations

Given a number from 1 to 24, output the kissing number to the best of current knowledge (some numbers will have more than one acceptable output). Knowledge of geometry is not essential as the outputs ...
2answers
895 views

### Is it a Rubik's Cube?

A venerated pass time of pedants is to point out that pictures of "Rubik's Cubes" (on t-shirts, posters etc.) are not actually solvable. The first thing that should be checked is that the cube is ...
6answers
725 views

### Distances to coordinates

There are n people on a 2D plane. Using distances between them we're going to find their positions. To get a unique answer you must make four assumptions: There are at least 3 people. The first ...
2answers
974 views

### Worst Case Manhattan Exclusion

Imagine a W by H grid of squares that wraps toroidally. Items are placed onto the grid as follows. The first item can be placed on any square, but subsequent items must not be within a Manhattan ...
2answers
1k views

### Random Golf of the Day #6: Roll a d20

About the Series First off, you may treat this like any other code golf challenge, and answer it without worrying about the series at all. However, there is a leaderboard across all challenges. You ...
3answers
668 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 use ...
11answers
2k views

### Empty a Swimming Pool . . . With Only a Red Solo Cup

You have a swimming pool that is filled to the brim with water. You need to empty it, but you can't think of an efficient method. So you decide to use your red solo cup. You will repeatedly fill the ...
4answers
4k views

### Drawing 3d nets - Platonic solids

This is a basic version of the rather more difficult Drawing 3d nets - Archimedean solids . I have a weakness for 3d nets which when cut out and folded allow you to make 3d shapes out of paper or ...