Simplify animation mask example

[Sirmadeira]

What problem does this solve or what need does it fill?

We have animations maks, the problem is the current sample seens overcooked. perhaps we should add a simpler one

What solution would you like?

Just a simple example, where one adds two single animation clip with mask and plays them, that way the idea of what they do is told way faster. Which does not happen in animation masks, which has a lot of UI bitwise operands and so on.