Diaper is a strange radical because sometimes it is a "big" radical, with other radicals inside it, and sometimes it turns into a "right-side" radical. Be warned!!!! Diapers come in all sizes!
Diaper (
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) is different from 'Moustache'(
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) because both of diaper's sides bend outward at the bottom. If you still have trouble telling them apart, think "FULL DIAPERS BULGE OUTWARDS".