Keyhole: the key that opens the Pyraminx

Keyhole flips the Beginners order around: it builds the top tip first —its vertex and two of its three edges— and leaves the third one out. That gap is the key: through it pass the turns that orient the bottom centres without undoing anything. Then you close the crown with the missing edge and only the three base edges are left. Seven formulas, four of them four moves long, and the longest has eight.