Pipe
From WikiManual
Picks two stack numbers and returns the OR comparison of their bits.
0 0 | = 0 -1 0 | = -1 0 1 | = 1 1 1 | = 1 -1 1 | = -1 0 -1 | = -1 -1 -1 | = -1
When one of the numbers is a power of 2, it adds both numbers.