Problem Statement

Produce a graphical or ASCII-art representation of a Sierpinski carpet of order   N.

For example, the Sierpinski carpet of order   3   should look like this: The use of the   #   character is not rigidly required for ASCII art. The important requirement is the placement of whitespace and non-whitespace characters.

Let's start with the solution:

USING: kernel math math.matrices prettyprint ;

: sierpinski ( n -- )
    1 - { { 1 1 1 } { 1 0 1 } { 1 1 1 } } swap over [ kron ]
    curry times [ 1 = "#" " " ? ] matrix-map simple-table. ;

3 sierpinski