The Ornithopter set calls for putting that 15100 into two stacked 63782 after they’re held together with a 32062 and it is such a pain. I ended up doing it in a different order, getting the 15100 into one 63782, then the other, THEN putting the 32062 through them. Eventually though I realized the 15100 seats a lot easier if you twist it while pushing it though, and that made my life better.