Minecraft wiki entry for Cocoa_bean_farming, associated text: A more compact 3x4x4 mechanism, but with 3/4 of the efficiency of the 7x7x3 model, may be made with a three-jungle-log stem. However, one side of the log stem is connected to sticky pistons with a block on the side of the middle piston. A torch is placed under the block and redstone is placed on top, then a lever is added to the block under the torch. To complete, plant cocoa plants on the three remaining sides of the jungle log stem and wait for them to grow. A flip of the lever and the cocoa beans can be harvested.