complexity theory – How to implement a Turing Machine that calculates log base 2 of n where n is a natural number and output in a unary format?

How would you construct a Turing Machine that calculates log2(n)?

The process must take in an input such as 4 and output the result in a unary format such as a 11 (11 = 2 in unary)?

In the final output tape, the tape should only contain blank symbols followed by a consecutive number of 1’s from the final head position.

Many Thanks