Two and a Half is the twenty-third mission in WorldBuilder.
Go to the far left of the map, and use one of the stacks of green bricks and energy bricks to build a Frog. Navigate the Frog carefully around the Alligator-infested waters, and grab the plans for the Buggy. Feel free to take the Frog apart.
Go to the middle of the map and build a Buggy. Grab the Duck plans off to the left, and start assorting the scattered yellow bricks into a stack of 5, taking precautions to avoid the Crab. Take apart the Buggy, and use the assorted yellow bricks to build a Duck. Use the Duck to grab the Tugboat plans located in the small pond.
Go back to the left of the map, and use the stack of blue bricks to build a Tugboat. Navigate carefully around the Gators to reach the goal.
Go to the middle of the map, and grab the Treebot plans off to the right.
Go to the right of the map, and build a Treebot. Move it in front of the tree, then build a Buggy. Block the Crab skulking around on the island with the tree, but be careful; wait until the Crab is far away enough for it not to be a problem. Once the Crab is blocked off from your units, as well as the lone yellow brick, take apart your Treebot, and pick up the lone yellow brick with your Buggy and place it on the stack of yellow bricks. Use the parts to build a Duck on the goal.