There was this thread about logic puzzles a while ago here at Sajha. Needless to say, it was quite popular. The thread was also a confluence of 'great' minds of sajha, who displayed there abilities to approach problems from different view points, not necessarily the correct point of view, however. One way to keep this thread moving is to come up with puzzles each time a puzzle is solved. And just to avoid any stress to Google Inc., I encourage people to phrase the puzzles as accurately as they can in their own words. ----- Here's the one that I would like to start with. --- There are two threads, with DIFFERENT lengths and DIFFERENT diameters. The threads are NOT uniform, each thread has different diameter at different points along the thread. But if you light up the thread at any one end, it takes exactly one hour for EACH thread to finish buring from one end to the other end. You can light up any end first-- it does not matter. Now, how do I measure 45 minuties by using those threads? ---- This is not a riddle, so the aim is not trick anyone in small details.