The Kind 7 ("Like") event has a "content" property where you can put whatever text you want. Blank is a standard "Like". Damus puts the hand gesture instead. But you could put any icon in there you wanted.
Discussion
Thanks. #[2] thinks there should be no Like... only Replies and Zaps. I am still mulling that over.
Same. On the one hand I get it -- likes are easy and therefore significantly less meaningful. Zaps require a bit of effort and value transfer. On the other hand, Likes also help a content creator gauge sentiment, which can be important.