Construct a regular expression for the set of bit strings in which every odd bit is 1.

For example, these are in the language: 10 (OK: 1 in position 1) 111 (OK: 1 in positions 1 and 3) 10101 (OK: 1 in positions 1, 3, and 5) 101111 (OK: 1 in positions 1, 3, and 5) (OK: There are no odd positions)

And these are not in the language: 0111 (BAD: position 1 is not a 1) 110 (BAD: position 3 is not a 1) 011001 (BAD: position 1 is not a 1 (nor is position 5))