Page 209 - Maria Constantino "The Knot Handbook"

STROP BEND

II)
c his is the knot that schoolgirls usually use to fasten together rubber bands for 'French
z T skipping', but loops of any material, and any colour, can be interlaced in this way.
w
a:i

Bring together two bights
I and insert one upwards
through the other.

..

Double the working bight
2 of the two back on itself.

secondary loop.