Each column is one consonant. Each row is one script that writes it. The stemma down the left margin shows which hand learned from which. Brahmi has more surviving descendants than any other script ever devised.

• Every cell is a syllable, not a letter. These are abugidas: a consonant carries an inherent a unless a vowel mark overrides it, so the first column is ka, not k.
• The column order is Indian. Consonants run from the back of the mouth forward, and within each place from unvoiced to nasal. No Semitic alphabet is ordered that way, and every script here keeps it.
• Tamil's gaps are real. Tamil has no aspirated or voiced stops to spell, so one letter covers what the rest of the family needs four for. A dot means the script genuinely has no letter there.
• Khmer and Thai kept the letters and changed their work. Khmer turned the old voiced series into a register that colours the vowel; Thai turned it into tone classes. Both are visible in the Unicode names.
• The round scripts are round for a reason. Sinhala, Malayalam and their neighbours were written with a stylus on palm leaf, where a straight stroke splits the leaf along the grain and a curve does not.

Three intermediate hands have no Unicode block and so no row: Gupta, between Brahmi and Sharada and Siddham; Pallava, behind Grantha, Khmer and Kawi; and Kadamba, behind Kannada and Telugu. Those connections are named in the row captions rather than faked with a substitute font.

Elsewhere: The Same Idea · The Missing N · Flat-Foot · Polite Company · Signs for Sounds · The Second Alphabet · Twenty-Two Letters · The Same Word · Heartwood · Every Language Family