四 is a Chinese hanzi, listed here under the keyword “four”. It is built from 囗 (erect) and 儿 (son). It appears as a component in 10 other characters in this index.
On KumiJi Glyph Explorer, open the parts search and type “erect” + “son”. 四 is among the results, together with every other character containing the same shapes.
Open 四 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.