This one was originally going to use the same construction as NoCoBo and Supersymmetry, but I soon realised that wouldn't work.
So I tried a triangle shape:
I quite liked that so started another one - only this time I forgot to weigh the yarn before starting and ended up miscalculating and fudging the shape:
But it turned out to be a happy accident because I realised I liked the rounded shape better than the triangle and decided to try to explore that a bit more and then made this one - which I really liked and which is the shape I used for the pattern - it still has all the advantages of no-cast on and no bind-off: