Taken from MAKING MEANING FROM A CLOCK: MATERIAL ARTIFACTS AND CONCEPTUAL BLENDING IN TIME-TELLING INSTRUCTION, a thesis by Robert Frederick Williams. Japanese hand calendar, which uses the structure of the hand to support naming the day of the week that corresponds to a given date;

This is an example of how things are cognitive artifacts:

Cognitive artifacts as material anchors for conceptual blends In recent work (Hutchins in press), Hutchins uses conceptual integration theory to analyze cognitive artifacts whose spatial configurations support reasoning about temporal relations. (...) Hutchins argues that the material structure, here the configuration of bodies in space, anchors the conceptual blend, stabilizing and maintaining the set of conceptual relations during subsequent reasoning or computation

Why do I blog this because it's a nice and visual example of cognitive properties of artifacts and embodiment.