

Task
Produce a graphical or ASCII-art representation of a Sierpinski square curve of at least order 3.

USING: accessors kernel L-system sequences ui ;
 
: square-curve ( L-system -- L-system )
    L-parser-dialect >>commands
    [ 90 >>angle ] >>turtle-values
    "F+XF+F+XF" >>axiom
    {
        { "X" "XF-F+F-XF+F+XF-F+F-X" }
    } >>rules ;
 
[
    <L-system> square-curve
    "Sierpinski square curve" open-window
] with-ui