Are you talking alphabet or just writing system? It's clear by the number of symbols it's a writing system of sorts (proto-writing). It could definitely be pi

Are you talking alphabet or just writing system? It's clear by the number of symbols it's a writing system of sorts (proto-writing). It could definitely be pictograms (probably IMO), but then again, cuneiform, hieroglyphics and Chinese writing all started as pictograms as well.