Click and wait until end.
Everytime you click green flag the new picture is generated.
It takes some time to generate one image, so be patient.
XOR is bitwise operation like AND an OR. This operation is in almost every processor, and is one of the fastest.
Xor can be used to create fractal-like images. Search "xor fractal" and "munching squares" in the web for example images.
for each color randomize t and plot (d1+t)^(d2+t)^(d3+t)^(d4+t), where d1-d4 is distance from corners, and ^ is xor operation.
Unfortunately scratch not provide a native xor operation and must be computed algorithmically. It make the process of generating image slow, so used look-up tables.