BEEmod
Partially Extended Piston Platforms
Very simple. An item very similar to the partial (quarter/half/3-quarter tile) blocks, but instead of them being completely solid, they'd be thin pieces extended by pistons. Useful for when you want to extend a portalable panel without extra blocks on the sides to cover up the sides of the partial block (especially because, if it's greater than half, you can put portals on the sides of the block, which could break puzzles).
Since it's a piston platform, perhaps it could also receive inputs to extend and recede. I think there's already one that goes out a full tile, but not partial tiles (and I think it's for "moving portals," can't confirm).
If you can manage. I'm assuming the 5 positions are receded, extended 1/4 tile, e 1/2, e 3/4, and fully extended?
I'd want to do positions that aren't already available, so 1/4, 1/2, 3/4, 1 1/4, 1 1/2?
I'm guessing it's 5 because of the 5 gel stream types? Those sound pretty good!
Cube Type. For a full-tile, you'd use normal Piston Platforms. I'm going to add white/black surfaces to that as well.
Would the fifth unused type be a surface that is extended one... "panel width" out, like this?
Although I assume this extension has already been implemented. If it has, how do I use it?
You can produce that via an Angled Panel item with no inputs, starting retracted.