Mnemonic comic for 入

rù = ru + Ø4: to enter / to go into / to join / to become a member of / to confirm or agree with / abbr. for 入聲|入声[ru4 sheng1]

Mnemonic symbol: an enter key like on a computer keyboard.

There is a special area in the space station's bathroom (Ø4) which is filled with bananas (丿), but you have to hit an enter key (入) to enter (入). Rachel Rhinoceros (ru) uses a finger (㇏) to press the button and get access to the bananas.