The triangle-shaped wheel is probably the easiest of the shaped wheels to use. It’s more awkward to use than the round wheels, but with care you can get a smooth pattern.
Some of its holes fall along the center line (holes 1, 5, 8 and 11). These holes produce symmetric loops.
The other holes are not on an axis of symmetry, and produce asymmetric loops which together make designs with a sort of pinwheel effect: a sense of rotation.
Whatever hole you use, the the triangle-shaped wheel produces a pattern with 35 loops using Ring 150/105.
NOTE regarding pens: I am using fine-tipped felt pens like the ones mentioned at this link, or in the sidebar.
Patterns with symmetric loops
Hole 1, at the pointy end makes a pattern that almost looks as if it had a circle drawn around the outside.
I changed pens as I went along, so that we might trace the path better with our eyes. What looks like a loop that you would draw with a round wheel is actually produced in two passes. You really have to feel this with your hand to understand it.
The inner part of the path is more apparent in the second pattern drawn with the next hole along the central axis of symmetry, hole 5.
The holes at the blunt end of the wheel produce the patterns on the left.
I like the apparent torus (donut shape) that appears in the middle of these patterns. It looks 3-dimensional.
The other holes are off the center line of the wheel. They produce loops that make me think of a foot in a sock, with a toe and a heel, pointing one way or the other.
Again, I’ve changed colors while drawing the designs so we can see the pattern. Can you see the sock pattern in each?
See if you can also detect the pinwheel effect, as if the pattern were a hurricane rotating.
Holes 2 and 4 are at the pointy end of the wheel.
But instead of forming a circle around the design, as hole 1 and 5 do, the toe and heel make a foot shape. The “arches” of the feet almost combine to make a circle just inside the toes.
I made the dark blue lines not for beauty but to see the asymmetry of the line.
The pinwheel effect is most apparent in the middle of the hole 2 pattern.
Finally, some spirograph designs made with the triangle wheel and two adjacent holes.
If you were using the round wheels, you could only achieve this level of complexity by combining several patterns.