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Ames Chair

Science Snack
Ames Chair
It’s all in the way you look at it.
Ames Chair
It’s all in the way you look at it.

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!

Video Demonstration
Ames Chair
Tools and Materials
  • Utility knife or other small, sharp craft knife
  • Clear, clean, straight-sided 2-liter plastic soda bottle, with the label removed
  • Shoebox
  • Stapler
  • Masking Tape
  • Scissors
  • Pen or pencil
  • Ruler
  • White 5 x 8 (12.5 cm x 20 cm) index card with at least one plain side (without ruled lines), or a piece of white posterboard cut to fit inside the short end of the shoebox
  • Two 1-inch (2.5 cm) brass fasteners (the exact size is not critical)
  • Pushpin
  • A copy of the two chair patterns available here (not shown)
  • Sewing needle with diameter no larger than the diameter of the pushpin
  • Thin monofilament fishing line (4-pound test works well) cut to about 15 times the length of the shoebox—about 15 feet (5 m)
  • Large rubber eraser, cork, pincushion, or similar (to hold the needle when it’s not in use, and keep the attached fishing line from getting lost or tangled as you work)
  • Two paper clips
  • 3 x 5 (7.5 cm x 12.5 cm) index card
  • Three 12-inch (30-cm) chenille stems in a bold color that will contrast with a white background (available online and in craft stores)
  • Needle-nose pliers
  • One-hole paper punch

Part I: Build the Viewing Box

  1. With your craft knife and/or scissors, cut off the top and bottom of the soda bottle so only a straight-sided cylinder remains. Cut through the cylinder so you can flatten it out, and then cut a square of plastic about 3 inches (8 cm) on a side. Make sure it has no markings, scratches, label residue, or distortions. This will be your viewing window.
  2. Cut a hole 2 inches (5 cm) square in one end of the box (see the photo below). Flatten the square of plastic, and staple it over the outside of this hole. (If the box is too thick to staple, or if the stapler won’t reach, you can tape it instead, but staples seem to hold better.)
  3. 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.

  4. 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

  1. Print the two chair patterns, available here, and cut them out.

  2. 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.

  3. 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.

  4. 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

  1. Tie a paper clip to one end of the fishing line. Measure 15 feet (5 m) of line and cut to length.
  2. Locate the brass fastener on the side of the box nearest the backs of the chairs. Measure out about 4 inches (10 cm) of fishing line from your paper clip, and wind it around the head of the fastener, letting the paper clip hang down when you’re done. These wraps will help hold the line tight inside the box (see photos below).
  3. Thread the end of the fishing line through the eye of the needle and tie a small knot to secure it. It’s time to sew!
  4. Begin by feeding the needle from the outside of the box through hole A (in the viewing screen), across the inside of the box, and out through hole a (in the plastic window).

    You’ll be doing more sewing, but stop here, before you pull the line through. Stick the needle into the eraser, and set it down on the table. Having the needle attached to a relatively large, visible object will not only let you to use both hands to work with the line, but will also help prevent the needle from getting “lost” and the line from getting tangled.

    With the needle safely anchored in the eraser, pull the line through holes Aa.
  5. Next, remove the needle from the eraser and feed it from outside the plastic window in through hole b, and then from inside the box out through hole B. As before, stick the needle in the eraser before you pull the line through Bb.

    Continue this process, sewing through holes C and c, d and D, E and e, etc., until you’ve pulled the line through hole J. To finish, bend the line from hole J around the outside corner of the box, past the round head of the second brass fastener.
  6. Pull the lines as tight as you can without warping the box. (You may be able to do this by just pulling on the free end, but if it works better, you can unwrap the line from the first fastener and tighten from that end as well.)

    Once you’ve tightened everything up, cut the line about 6 inches (15 cm) beyond the head of the second brass fastener, and tie the remaining paper clip to the end of the line. Keeping tension on the line, wrap the free end around the second brass fastener until the paper clip comes close to the fastener head.

    You should now have ten separate lines tightly strung from end to end inside the box, as shown in the photo below. If you want, you can tape the paper clips to the sides of the box to keep them out of the way.

Part IV: Create an “Ames Chair”

  1. Cut two of the 12-inch (30 cm) chenille stems into 3-inch (7.5 cm) pieces. Then cut the remaining chenille stem into 2-inch (5 cm) pieces. You should end up with eight 3-inch (7.5 cm) pieces and six 2-inch (5 cm) pieces, for a total of 14 pieces.
  2. Using needle-nose pliers (or your hands, if you prefer), bend each piece so it has a 90-degree tab about 1/4 inch (6 mm) from each end, as shown in the drawing below.

  3. To “build” your chair, you’ll need 11 chenille stem pieces, in any combination you like. Set the remaining three pieces aside—you won’t be needing them.

    Start by using one piece of chenille stem (short or long) to connect line Bb to line Cc, and use your fingers or the needle-nose pliers to bend the tabs so they wrap around the lines, holding the piece in place. It doesn’t matter where on the lines you put the chenille stems, as long as each end is somewhere on the right line and the piece is located in the back half of the box.

    The drawing below shows two possible ways to do this, using either a long or a short piece (either is OK). It doesn’t matter what angles the piece forms with the lines, or how the piece is oriented, as long as it doesn’t pinch the lines together or spread them apart.

  4. From here on, working in the back half of the box, connect lines as noted in the table below to make all the parts of the chair:

    When you’re done, you should end up with an array of chenille-stem pieces that look something like the photo below.
  5. Use the one-hole punch to make a hole near the middle of the 3 x 5 (7.5 cm x 12.5 cm) index card. If the punch won’t reach the center of the card, try bending the card and punching half a hole on the bend. Alternatively, you can use the tip of a pen or pencil to punch a hole; it’s not critical that it be perfect.

    Place the card over the plastic window so your view through the hole is approximately centered on the pattern that defines the back of the chair (see photo below). Then staple the top of the card to the end of the box. (If the box is too thick for staples to work well, use masking tape.) Gently fold the card upward to make a crease just below the row of staples. This “hinge” will allow you to lift the card to expose the clear plastic window when desired.

    Your Ames Chair viewer is now in place.
To Do and Notice

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).

What's Going On?

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.

Going Further

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.