The Steps of TopSpin (Coins in Ascending Order)



Step 1

The First 16 Coins

When the first 16 coins are placed,
your topspin will look like this:


No particular algorithm
Step 2

The 17th Coin

Coin 17 must first be placed in position 1 or 2

If coin 17 is in position 1, everything is fine, otherwise there is one possible scenario:

When the 17th coin is placed,
your topspin will look like this:



Case where coin 17 is in position 2


Step 3

The 18th coin

You must first place coin 17 in position 1

If coin 18 is in position 2, everything is fine, otherwise there are 2 possibilities:

When the 18th coin is placed,
your topspin will look like this:



Case where coin 18 is in position 3



Case where coin 18 is in position 4

the coin is then in position 3, so you must perform the algorithm opposite
Step 4

The 19th and 20th pieces

First, piece 17 must be placed in position 1

If piece 19 is in position 3, everything is fine; otherwise, there are two possibilities:

When the 19th and 20th pieces are placed,
your topspin will look like this:



Case where piece 19 is in position 4



Your topspin is solved.