On Kwontom Loop forum, someone asked for Masyu puzzles, so I copied my LoopDeLoop silverlight game engine from last weekend and spent a day hacking it to change it to be like Masyu instead.
The result is http://www.themissingdocs.net/Twist.html.
Still a work in progress, Masyu puzzle generation is much more annoying than LoopDeLoop, due to a large proportion of possible loops do not have a valid Masyu puzzle associated with them. Therefore where LoopDeLoop can generate puzzles in sizes like 20×14, Twist struggles to get much further than 8×8. I will at some point be looking at an alternative puzzle generation strategy, but not tonight.
Update: I’ve fixed the slow puzzle generation using a cool little trick – it now can do 15×15 in a decent time.