So in, like, 5 minutes I made this block, not really that good.

But basically I made this topic to that everyone can add stuff, I will keep the script above up to date :)
Goals:
Custom Blocks
Variadic inputs
Multiple blocks at a time
Keeping what is currently in the scripting area
You must use dev mode
snap dev 
It is supposed to replace all blocks in the scripting area with the scripts you entered.
Though, whenever I try something it shows a grey "Undefined!" block.
You must be on the dev version for this to work. That's because it uses the selector function in the [] of block {}
block which is introduced in Snap! 10.
https://snap.berkeley.edu/versions/dev/snap.html
Anyone have ideas on how to make multiple blocks work?