# Very Simple Triangles

Write a program or function that takes in a positive integer (via stdin, command line, or function arg) and prints or returns a string of that many of these small triangles tiled together, alternating which way they point:

 /\
/__\


This sole triangle is the output if the input is 1.

If the input is 2, the output is

  ____
/\  /
/__\/


If the input is 3, the output is

  ____
/\  /\
/__\/__\


If the input is 4, the output is

  ________
/\  /\  /
/__\/__\/


And so on. Your program must support inputs up to 216 - 1 = 65535.

Details

• The leftmost triangle always points upwards.
• There may be trailing spaces but there may not be unnecessary leading spaces.
• There may be an optional trailing newline.
• Note that for 1 the output is two lines long but otherwise it's three. This is required.
• The shortest submission in bytes wins.

# C# (.NET Core), 151 bytes

Without LINQ - 3 string array.

Like most of these, this fails if the integer goes over the max char count per line for stdout.

p=>{var s=new string[3]{ "  ","",""};for(var j=0;j< p;){if(j++%2<1){s[1]+=j==p-1?@" /":@" /\ ";s[2]+=j==p-1?@"/":@"/__\";}else s[0]+="____";}return s;}


Try it online!

# Retina, 88 bytes

K  ____¶ /\  /¶/__\/
%....+*$& %(.+)\1$
$1 ( (____)*)__(¶.*) /(¶.*)/$1$3$4
G\S


Try it online! Explanation:

K  ____¶ /\  /¶/__\/


Replace the input with a pair of triangles.

%....+*$&  Multiply the triangles by the original input. %(.+)\1$
$1  Divide the triangles by 2. ( (____)*)__(¶.*) /(¶.*)/$1$3$4


Remove the left-over half triangle.

G\S


Remove the first line if it is now blank.