The poem sets up a small, odd picture: a "perfect child" who dances along to a clock. The clock seems to set the rhythm, and the child moves to it happily. Then the second half turns. The child answers the clock only with "a tic but no talk," so the response is mechanical, a twitch or a tick, not a voice.
The speaker's feeling is hard to pin down, and that is part of the effect. The word "perfect" could be admiring, but it could also be uneasy, as if the child is too obedient, too much like the thing it dances to. The judgment is quiet and left for us to make. The child seems to become a kind of clock itself, ticking back instead of speaking.
The mood is cool, slightly eerie, and tender at the same time. Because the lines are so short and spare, the poem itself feels like ticking, with each pause a small beat of time passing.