The harp is a lie.

[Gramul]

How many harps have you seen that only have 4 strings?

How many harps have you seen that have strings THAT thick?

http://www.acoustics-engineering.com..._with_lyre.jpg
http://www.historyforkids.org/learn/...tures/lyre.jpg
http://www.eleonoravulpiani.com/lire/mosaico%202.jpg
http://www.zeldawiki.org/images/7/71/Medli_TWW.png

There are actually probably 5 or 6 strings on it. The 5th string could be hidden behind the top "bow" part on the intrument, and the 6th might be the bowstring itself when folded. Whatever the case, it's an artistic interpretation of an instrument and as such is up for iconic simplification.