A similar arrow illusion available here:
From Etsy: Buy Now: Stubborn Arrow Illusion
In or Out Illusion: this 3D printed sculpture incorporates the now famous Stubborn Arrow Illusion and features both a left and right handed version. These ambiguous object illusions are a fairly recent invention by mathematician Kokichi Sugihara of Meiji University in Japan which take advantage of a clever combination of perspective, and viewing angle.
The best Klein Bottles are made by Cliff Stoll, astronomer, mathematician and artist. Every one-sided, zero volume bottle is packaged and shipped by Cliff himself. Get one today!
From ACME Klein Bottles: Buy NOW Klein Bottles by Cliff Stoll
Wikipedia has great details on the Klien Bottle, and the amazing Cliff Stoll.
The Klein Bottle: 3D representation of a four dimensional mathematical object with one side, no edges, and zero volume. Kind of like a Möbius strip with no edges.* Math meets glass art! Many thanks to Cliff Stoll for this kind gift and a great visit including a wonderful tour of his collection of mathematical oddities. *only achievable in 4D.
Amazing creations made here:
From Etsy: BUY NOW
Spiral Gear Set
Original 3D print files available here:
From Thingverse: Spiral Gear Set
Logarithmic Spiral Gears: an extreme example of non-circular gear sets. This set is based on the famous Fibonacci spiral and evokes the cross section of nautilus shell with internal chambers. If one gear of this set is turned at constant speed, the other will turn with an varying speed. A kind gift laser cut at @hsvsteamworks and based on 3D prints of Misha Tikh and the research of Balint et al.