You can see the man sawing between his teeth, the high-speed tooth-pick darting in and out like a mouse in a house with a hole. 

… the seed-pearl teeth, where a tooth-pick ran ceaselessly in and out, in and back again, like a mouse in a cage. 

Source: Louis Golding, Good-bye to Ithaca (London: Hutchinson, 1955), p. 48

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