Consider the relationship between base -2 and binary representations, focusing on how digits are transformed when switching bases.

Observe that multiplying by 0x5555555 (which is 10101010... in binary) acts as a bitwise mask—how might this help isolate or transform digits in the base -2 representation?

Explore how Schroeppel’s formula for base -2 can be inverted or dualized by leveraging the properties of 0x5555555, particularly its role in separating even and odd positions in the binary expansion.