Wiktionary
paint-by-numbers
a. 1 (context of a picture English) Made from a painting by numbers kit. 2 (context figuratively English) By rote, without thought or creativity.
Usage examples of "paint-by-numbers".
The truth was that some anonymous painter had filled in Da Vinci's sketch like a paint-by-numbers years after Da Vinci's death.
On the scratched mahogany table beneath the window squats a crude peacock carved from cheap pine with an unsteady hand and, leaning against the burnt-out lamp, an unfinished paint-by-numbers canvas of a bug-eyed cow Mother bought at a Kmart in Mason, Kentucky, on her last and final visit to Cousin Dewey's.