So you know that original Pushy-V Pully-H mechanic? Well, what if there was a way to merge 2 crates into one? So for example you can turn a One Push Crate and an Ice Crate into a One-Pushy-V Slidey-H Crate. The possibilities are (not) endless!
That's way too complex to be a feature, so instead, I will make it so you can turn the "Pully-H" part into any crate you want, except the normal one and some certain crates.