Blocks for Undo and Redo Buttons for Digital Doodle?

[AppInventorAmateur]

Experts, I need help! As a project, we need to do a digital doodle app with extra features. I have done all the basics (change background, change paint color, etc.) but i do not know the blocks for undoing and redoing an action. :( Please, please help me! I really want to add Undo and Redo buttons for my Digital Doodle.

PS. I use App Inventor 2 :)

[SteveJG]

Try the forum threads here  https://groups.google.com/forum/#!searchin/mitappinventortest/undo$20redo      I believe there are even on or two aia files discussion how to undo / redo painting.

Is this what you need?

Regards,

Steve