Dâl is for Dinar

http://alifbatourguide.com/the-arabic-alphabet/dal/

Dâl is the fourth basic shape. We started with the shape of Alif (population one). Ba, with that simple plate shape, plus dots, gave us the second and least interesting of the shapes. Jîm was the mold for three or four additional letters. The Dâl shape marks the end of a series (with one companion letter to follow). The four shapes in sequence spell abjad. ابجد. ) .د .ج .ب .ا)

Dâl in its simplest form is just two lines which splay out leftward from a point usually at the base line. In calligraphy the upper line can be thick or thin, drawn with the full width of the reed’s edge, but it is almost always nearly upright, leaning at perhaps the 11:00 position. The lower line ramps down to the left, usually at a slight angle, perhaps 8:00.  From the Nabataean predecessor, an inverted L, Dâl has rotated not quite 180 degrees clockwise. More schematically, we can imagine it as simply two thirds of an equilateral triangle with the left side missing. Its Greek counterpart, Delta, adds the third side, to form the complete triangle.

Perhaps because it is a simple letter, in calligraphy there is room for considerable variation. It may curl up as it tapers. You may see the lower mandible almost join the upper one. There are lengthened versions which allow them to stretch out left in long, straight parallel lines.

The Arabic Alphabet: A Guided Tour

by Michael Beard

illustrated by Houman Mortazavi