From A Second Treasury of Knitting Patterns by Barbara Walker.
This rendition of Grand Trefoil closely mirrors Walker’s original instructions, in that it represents (yo) twice
with two yo
symbols and it explicitly shows the drop stitches. See also Grand Trefoil, which represents (yo) twice
with a special symbol that implies “wrap twice when creating this yo, but on the following row drop one loop to create a single exaggerated yo.”
See also this Ravelry post.
Shown with a cast-on count of 18 stitches.