Katamino Compact is one of the most clever "Fit in the pieces" puzzles ever created. The twelve different shaped pieces are called pentominoes. A cluster of any 4 (or more pieces is called a "PENTA". One makes a variety of different size PENTAS. The playing tray has 10 slots (numbered from 3 to 12). Use the black spacer bar to change the size of the playing base. The object is to fill in the open space with a group of puzzle pieces. In most instances there will be numerous solutions using a different group of pieces. Move the bar to enlarge the playing space and attempt to find as many ways as possible to fill the open space with as many different groups of pieces. Obviously the larger the playing space the more puzzle pieces that will be used. The difficulty level increases the more pieces that need to be used. Puzzle measures approximately 7.25 inches long, 4.25 inches wide and 1.5 inches thick. Underneath storage drawer holds instructions and challenge card. Delightful puzzle for ages 8 to adult. Great for travel. Lots of play value as there are so many different challenges and possible solutions.