Instructions
Choose the "Create Mode" function. Press on the square button on your controller when your sack character appears to access the popit, which is a menu hovering above the character's head with a lasso.
Select the "Objects" icon that looks like a tied bag. Access the subsections of the popit by pressing right on the controller. Click on the "Media Molecule" menu to pick the premade objects you want. Choose the sponge from the menu.
Move the sponge to the area where you want to place it by using the left analog stick on the controller. Enter the popit menu and use the right arrow to select the "Tools" function that looks like two gears. Choose the motor-bolt connector.
Place the motor bolt on the sponge so that it can rotate. Listen for the whirling noise of the connector bolted in place. Press the square button to open the tweak options menu.
Decide on the speed and direction that you want the motor bolt to rotate. Continue modifying your sponges until you create the world you want.