The author used symbols which are not displayable in text. full: a small vertical line (forming somewhat of an uppercase "I") a small horizontal line on the right bottom (thus forming somewhat of an uppercase "L") a small vertical line closing the right bottom (thus forming a square box with no top line) lastly, a small diagonal line from half-way up the right vertical pointing upper-left (thus forming somewhat of an uppercase "Y") box: all of the lines of the "full" symbol, surrounded by another box vertical: a small vertical line (forming somewhat of an uppercase "I") ell: a small vertical line (forming somewhat of an uppercase "I") a small horizontal line on the right bottom (thus forming somewhat of an uppercase "L")