I’ve posted a new library at Github for controlling HL1606-based RGB LED strips, along with some details on where they can be purchased and how they can be set up. I’ll post examples later, once I get some cool patterns up and running.
I’m sure this information is available elsewhere, but I couldn’t find it with a quick google search — the two hardest 8-puzzle instances are:
8 6 7 2 5 4 3 . 1 6 4 7 8 5 . 3 2 1
Both require at least 31 moves to solve. All other instances can be solved in 30 moves or less. (Found using breadth-first graph search, starting at the goal state). Somewhat interestingly, they are not obviously symmetric, but differ only in the locations of the even pieces.
I had some old slides in Mac PPT 2004 format that I wanted to put into a new Keynote 2008 presentation. The initial ppt file was about 3 megabytes, but when I opened it with Keynote it blew up to something like 400 megs. Turns out there were a bunch of relatively small images that were being blown up to 15 MB tiff files in the translation. The solution was to open the original file in Mac PPT 2008, and save as .pptx format with image compression turned on (High Quality). Then, open that file in Mac PPT 2008 again, and resave a further time back in .ppt format. Finally, open that .ppt file in Keynote, and the converted presentation should be of reasonable size (mine was 5 MB). YMMV.