Show HN: Draw 2-bit masterpieces in the browser linearly, back is undo

What is it supposed to do? Because I can't get any reaction on any controls (mouse, keyboard, buttons etc) in Firefox 45. Clean install with no addons whatsoever.

Update! Actually I get this JS error: SyntaxError: in strict mode code, functions may be declared only at top level or immediately within another function

Why did you use that stupid strict mode? It has no real benefits...