Mastering the basic alphabet is not enough to be able to read and write Siddhaṃ, because there is a special way of writing two adjacent consonants - such as rma, ttva, or jra. In the case of rma (image left) you write the top half of r with the bottom half of m. Vowels are indicated as for individual consonants. It's important to get the order correct - tna and nta are easy to mix up for instance. It is possible to stack more than two consonants: ttva for instance (see below).
The table below, is based on one in John Stevens' Sacred Calligraphy of the East. It shows how the top and bottom half of the consonants look. There are a few irregular items, such as the bottom of ra or ṇa.
Note that some consonants are only shown with a top or bottom. This is as they appear in Sacred Calligraphy of the East.
Examples of Common Conjuncts