Instructions needed

I'm sorry for this ugly creation, I need some instructions for the oekaki-applet How do I "copy" a part of a drawing and slide it aside? I've seen drawings consisting in which certain shapes appear more that once, exactly the same. I think I need the mask-thing but I can't get it to work! Thanks in advance!

"I've seen drawings consisting in which certain shapes appear more that once, exactly the same." Dang, what language is that! I meant to say: "'ve seen drawings consisting of certain shapes appear more that once, exactly the same."

hi shunt, 1. mask the color you want to copy 2. slide the drawing 3. select for example the bezier line tool (just select it, don't draw anything) 4. press undo also works if you reverse the mask, except it will copy every color but the masked one.

Thanks a lot idwtwwr!