*1 unit on 0-1-2-3 (corner, pays 1 unit profit)*

2 units on 31-32-33-34-35-36 (double street, pays 4 units profit)

1 unit on each of the following 5 splits: 8-11, 13-14, 15-18, 17-20, 27-30 (each split gives profit of 10 units)

It means, we can play this trick, in a variety of ways. We are basically covering 20 numbers with different bets.