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Short pieces of chenille stem arranged inside a box look like a random jumble of line segments—until viewed in the proper perspective.
Note: This activity is detail oriented and time intensive. It’s done by threading a long length of fishing line through twenty small holes, and then attaching short pieces of chenille stem to create a suspended pattern. When you look through a viewing hole, that random-looking pattern resolves into the form of a chair. If you think being a watchmaker is something you’d hate, then you might want to rethink doing this Snack!
Part I: Build the Viewing Box
Using the 5 x 8 index card or white posterboard, cut a piece that’s almost as large as the end of the box. Staple it inside the box, opposite the clear plastic window, as shown in the photo above. (If using the index card, be sure the plain side is visible.) This is your viewing screen.
Using your craft knife, make a small slit about 1/4 inch (6 mm) long in each side of the box, about 2 inches (5 cm) away from the end with the white viewing screen, and about 2 inches (5 cm) down from the top. (The exact location is not critical, nor is it critical whether the slit is horizontal, vertical, or in between). Then, insert a brass fastener into each slit, with the round head on the outside of the box and the fasteners on the inside. Bend flat to hold in place. (See photo in Part II, below.)
Part II: Set the Chair Patterns in Place
Print the two chair patterns, available here, and cut them out.
Center the small-chair cutout over the plastic window, on the outside of the box, and tape it firmly in place, as shown in the photo below. Then center the large-chair cutout on top of the stapled-on viewing screen, on the inside of the box, and tape it firmly in place.
Using the pushpin, poke a hole at each of the ten lettered points in the small-chair cutout (a–j). The holes should go completely through the plastic. Be sure the drawing stays in place as you work. Then use the pushpin to poke a hole at each of the ten lettered points in the large-chair cutout (A–J). The holes should go completely through both the index card or posterboard and the end of the box. Again, be sure the drawing doesn’t move around as you work.
When you’re done, remove both drawings—but keep them available nearby to use as references as you work.
Part III: Sew the Pattern Lines
Part IV: Create an “Ames Chair”
When you look down at the chenille stems in the box, the arrangement should look random (see photo below).
Now close one eye and look through the viewing hole. The chenille stems should look like a little chair! You may be able to improve the appearance of the chair by straightening, pinching, or otherwise tweaking the chenille stems (see photo below).
When you look at the chenille stems through the viewing hole, you don’t have accurate depth perception because you’re viewing them with only one eye. Without depth perception, each chenille stem looks straight, regardless of the angle it’s at. You also can’t tell whether a segment is a short chenille stem close to you, or a longer chenille stem farther away from you.
The fishing lines inside the box are angled according the principle of perspective. Each corresponds to a point on the chair. That’s why a chenille stem that connects two of these lines will look like it connects two points on the chair. This is true no matter how the chenille stem is positioned, as long as each end is on its appropriate line. When you look through the viewing hole at the chenille stems, your brain perceives an array of line segments connecting the points of a stick figure, and sends you the message that you’re looking at the form of a chair.
The title “Ames Chair” is in reference to Adelbert Ames, Jr., born in 1880, who worked in visual sensation and perception. Ames is most widely known for developing the Ames Room, the classic “distorted room.” When an outside viewer looks into an Ames Room through a specified opening, a person moving around inside the room appears to change height. As with the Ames Chair, the Ames Room utilizes perspective to create its illusion.
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Attribution: Exploratorium Teacher Institute