u/DiegoScire

I want to learn the trick Weighing the Cards by juan tamariz from his book Mnemonica. In page 199 is this explained:

,,Since you have previously prepared the card case by breaking its bottom left edge, near the flap, you can easily glimpse the index of the bottom card by pulling down slightly with your left thumb, and thereby determine the number of cards cut.‘‘

I don‘t really understand how it should look like and ask chatgpt but i don‘t think it is the right answer.

Can someone explain me this?