Who finished building the frozen wheel and when?

this might be one of the biggest questions in lost after "Across the Sea". as we all know mib was building the frozen wheel(why is it frozen anyway) but he did not get to finish because his adoptive mother knocked him unconscious. when he woke up, the well was filled up with dirt. now, explain how it is later finished! who did it? when? was it the same people who built the temple, the statue of tawaret, and all of the islands underground tunnels? we may never know. anyone have any ideas on what is now one of the biggest mysteries in LOST?