I've been practice for a week now, and I tried many cups that I purchased from other websites but
non of them really work even though I have the right technique. But after I started use this cup, I
success rate dramatically increase, and within a day, I can even stack 4 dices very easily.
However, the shortage of this cup is that it's height can only hold maximum 4 dices and it make dice
stacking way easier than usual.