Matthew 11:16 also uses 'to what shall I liken this generation?' — the same comparative question style, here about a generation.

Luke 13:18 asks 'What is the kingdom of God like? To what shall I compare it?' — a direct Synoptic parallel to Mark's introduction.

Luke 13:20 repeats the same rhetorical question about the kingdom, then gives the yeast parable instead of the mustard seed.

Matthew 13:31 directly parallels this verse with the same mustard seed parable introduction.