Triangular Box Kite (customizable)

Joints for trinagular box kite. Default is for 4mm round sticks.

####You will need:
* 6x corner
* 4x mid
* 2x mid-wing

---

####Recomended material and sizing:
* 4mm laminate tubes (cheaper than carbon)
* ripstop cover
* size: length 1m, triangle side 0.50m

---

####Update - rectangular sticks support:
* set `$fn = 4`
* notice that `inner_d` is outer diameter of the stick (= diagonal size of rectangle), so use `d = a*sqrt(2)` where `a` is side of the rectangle

---

Plans are copied from this site: http://www.stavimedraky.rozhled.cz/index.php?code=krabicovi