It's most likely meant to be Delta, as used in mathematics and science (which is typically smaller than the Greek letter). Not only is the Delta in the Greek character similarly shaped, but Lambda is similarly distorted in the greek character set. Likewise, A, N, V, Y, K (arguably), and W (arguably) are distorted.
Although originally the character Δ began life as 𐤃 (named dalet, meaning door) so it should be a door, not a house (he says with a wink) and that β should be the house (from 𐤁, bet, meaning house).
