Rounded version of the "Infinity cube lampshade": https://www.thingiverse.com/thing:3520798

Simple but stylish lampshade for an E27 LED lamp based on "Infinity cube rounded": https://www.thingiverse.com/thing:3522230

Print:

• 3 frame parts with pins,
• 3 frame parts without pins,
• 6 pins,
• 1 ring

then fasten/glue them.

The inner diameter of the ring is 38mm, so you may need to scale the whole model to fit your lampholder. Or you can use a simple editor (e.g. Tinkercad) to modify only ring part.

Enjoy! :)