面壁

面 = 丆 + 囬 : Mnemonic symbol: a spray flask with one of these liquids which make a surface super slippery.

In the anthill's bathroom (an4), Marilyn Monroe (mi) wants to set up a wind wheel (丆) on top of a closet (囬). Just as she tries to fix it she slips and falls down, the wind wheel crashing on the floor. She didn't notice that somebody used a can of non-stick coating (面) on the closet's surfaces (面).

壁 = 土 + 辟 : Brunhilde (bi) was checking out the safety of the space station and found that the bathroom (Ø4) is a weak spot in the defence line if there should be any attacker. Thus, she decided to build a rampart (壁). She cannot do it alone though, so she asked the jade dragon (辟) for help. Together, they build the rampart out of earth (土). In this way, they will be able to fend off (辟) any intruder.