to reflect on; to ponder over
思 (sī) · 9 strokes
Thought is associated with the head (囟) and heart (心). 囟 is also a phonetic component.
考 (kǎo) · 6 strokes
Depicts an old man (耂) with a cane (丂). Originally the same character as 老. Based on the original meaning "old father". The current meaning is a phonetic loan.