The number of chocolate (black regions) is prime. Normal Chocolate Banana rules apply. Rules: Paint some of the cells black. Black cells linked orthogonally must always form a rectangle (or a square). Non-blacked cells linked orthogonally must not form a rectangle (or a square). A number indicates the area (the number of cells) of the orthogonally region containing this cell. The solution is unique except its reflection. You do not need this information to solve the puzzle. Click on the image to use the online solver and view the rules ..read more

What is represented below? The answer is a 9-letter two-word noun ..read more

The following position, where one player has borne off all their checkers while all of the other player's checkers are on the bar (thus losing a backgammon), is reachable by a legal sequence of dice rolls and checker movements from the standard starting position of backgammon. How can this position be reached in the fewest number of turns? To clarify A player rolling both dice and then moving their checkers (or not) based on the numbers rolled constitutes a turn. A player rolls even if they have checkers on the bar but their opponent's home board is completely closed (two or more checkers on ..read more

You wake up in a bed - not yours - your eyes squinting from the bright sun in the window. It’s an escape room, you ponder. I need to find a clue. A piece of paper is taped to the window, containing an encrypted first word: KZIPIPJL VNWRRYQRWRBM UO PSBMSF OA IPBM TUIPYIET JLWRTUVNIPPSETSF. There is a single letter we need, to escape out free. You only get one try, so think about it for your prize. First posted on my Twitter ..read more

Find the algorithm that was used to create the following sequence of numbers: BAH BAA BBA BAD BBD BAG BBG BAJ BBJ BBC BCC BBF BCF BBI BCI BCB BDB BCE BDE BCH BDH BDA BEA BDD BED BDG BEG BDJ BEJ BEC BFC BEF BFF BEI BFI BFB BGB BFE BGE BFH BGH BGA BHA BGD BHD BGG BHG BGJ BHJ BHC BIC BHF BIF BHI BII BIB BJB BIE BJE BIH BJH BJA CAA BJD CAD BJG CAG BJJ CAJ CAC CBC CAF CBF CAI CBI CBB CCB CBE CCE CBH CCH CCA CDA CCD CDD CCG CDG CCJ CDJ CDC CEC CDF CEF CDI CEI CEB CFB CEE CFE CEH CFH CFA CGA CFD CGD CFG CGG All numbers are in base 10 ..read more

Since 37 is my favorite integer and π is my favorite number, here's another puzzle: Normal Chocolate Banana rules apply. Rules: Paint some of the cells black. Black cells linked orthogonally must always form a rectangle (or a square). Non-blacked cells linked orthogonally must not form a rectangle (or a square). A number indicates the area (the number of cells) of the orthogonally region containing this cell. Click on the image to use the online solver and view the rules ..read more

This too is a Colombian Sudoku by Xavier Castillo. The usual rules apply. The dots outside the board on top indicate how many cells in the corresponding column or row of that board contain precisely the same digit as is to be found in the same cell of the solved Sudoku below. Additionally, digits on each of the two diagonals must all be different ..read more

Your goal is to maximize the absolute difference of the numbers marked ?. (? marks indicate region areas. They may or may not belong in the same region which another number or ?. They may or may not be shaded.) Answers must prove their claim (and provide a construction). Normal Chocolate Banana rules apply. Rules: Paint some of the cells black. Black cells linked orthogonally must always form a rectangle (or a square). Non-blacked cells linked orthogonally must not form a rectangle (or a square). A number indicates the area (the number of cells) of the orthogonally region containing t ..read more

Can you tile a 15x16 rectangle using eight rectangles whose sizes are 1x2, 2x3, 3x4, ... 8x9? No two rectangles can be the same size ..read more

The Persistence Of Memory The Memory Labyrinth Rules You are currently just behind the door in the bottom right. You must walk through each of the other rooms before returning to the first room. Steps must be to horizontally or vertically adjacent tiles - no diagonal movement. You may not step on the same tile twice. In the middle room, you must step on every tile. In the left room, you must step on every tilein the S-shaped region. Every time you step between two tiles, a line will be drawn between those two tiles' centers. This means that the line will trace out your path along the tiles, m ..read more