Bug fixes:

    else {   }.
    Standalone mistreatment of < and >

Improvements:

    static variable construct.
    once { ... } block.
    Shorthand: loop(n, x { ... }).
    Opacity.
    Rotation.
    Randomize.
    star() and fill_star() functions to draw n-vertexed stars.
    tan(x), tangent of x degrees.
    Power operator ^ for arrays.
    Modulus for arrays.
    Removing vestigial code.
    Renaming some long-winded functions.

Other:

    Minor refactoring of the polygon drawing code.
    set_default_line_width ==> set_default_line_thickness
    Removing unnecessary prototypes from in-browser JS code.