Literally: same – construction – different – melody
Alternately: The technique or methodology used in making two things is the same, but the style is different. Things appearing markedly different despite being born of fundamentally the same character or craftsmanship. This phrase is especially used to describe artistic works such as poetry or music.
Notes: Some people occasionally replace 工 with homophones 巧 or 口 (perhaps mistakenly taken from compounds such as 異口同音), but this is considered an error.
This phrase originally comes from the writing of Tang-era neo-Confucian writer Han Yu.