·    The logogram for this word appears to be Madrid Codex C2 and is the only instance known – the search in MHD “All - Blocks” on “blcodes contains AP2b” gives only this one hit. In other words: there are no known instances of this logogram in the Classic Maya corpus (of MHD).

·    Known from the Dresden Codex. Knorosov used the iconography (which portrayed a dog) and the syllabogram-only spelling (which labelled the iconography) and the fact that cognates in the modern Maya languages had words resembling tzul for “dog” to support his idea that some of the glyphs were sound-based.