Rules: Locate 12 blocks into the grid, each having the size 1×3, without touching each other from the side. These 12 blocks should contain all the possible combinations of the numbers 1,2 and 3. Half of the blocks should be located horizontally and half should be located vertically. Each half group must have different blocks. Numbers in the grid indicate the sum of the numbers touching their cell from the sides.
Background: This type is one of my inventions. I used first time in 2008 IPST December’s Contest. Then I made for OAPC 2, appeared in WPC French Qualifier 2009, and finally used in Individual Finals of 18th WPC.