Summary

A mandala loop which is significantly larger than any I could find online.
Designed in fusion 360 (included in the files available to download) and is parameterised for the radius of the hoop and the number of segments. Also other sizes (like the length of the connecting prongs). I've made the connecting prongs have a 1 degree taper, so they slide into place with little / no force - as long as you clean off the supports from the prong - which will be needed. The prong is a square on its side (a diamond), so as to avoid any supports being needed for the corresponding socket.
In principle it may be possible for the segments to not be glued (as when used, the tension from the mandala should keep them all together), but I think a little super glue dribbled into the prong socket will be sensible.

v4 : uses a prong gap of 0.3mm - which may be a little loose, depending upon your printer. These have a cross section of 10x10 and a prong size of 4mm.
v5 : uses a prong gap of 0.2mm - which is a little tighter and worked better on my printer. Cross section and prong size like v4.
v6: uses a cross section of 6x6 (for smaller diameters rings) and a smaller prong size - 2.5mm. Prong gap as for v5

Rather than scale the parts in your slicer, if you want a particular sized hoop, send me a message with the hoop diameter you would like, and the maximum length of segment you can print, and I'll add the appropriate part here. I've just added a larger (700mm diameter) of the v6 (6x6mm cross section), for someone to try out - we shall see if it feels robust enough - watch this space.

Currently I've included files for plates that are limited to 200 and 300mm.
The file name includes the diameter of the hoop, the length of each segment and how many you will need to print to make a hoop. Also the version of the hoop - as above.

I suggest you initially print just two segments and ensure they fit together such that you can stick them together nicely with some superglue. If they are too tight or too loose to glue, let me know and I'll see what I can do.

I printed this using PLA, 0.2mm layers, three walls, 20% infill with tree supports.
I print with the flat back of the segments on the plate.
I've included a picture of an assembled 600mm (diameter) hoop with a banana for scale.