Kitbashing is the practice of taking components from a pre-existing game to use for your prototype, as opposed to purchasing them or making them from scratch.
I’m one of those designers who also dabbles in graphic design and, as a result, often finds it difficult to do proper “fail fast” prototypes.
So I’m making this area control-deckbuilder mashup about the 1970s NYC graffiti scene and instead of constantly agonising over the map I went and got the El Grande board out.
Turns out that this quick bit of kit-bashing helped me really quickly come to the realisation that I needed to have the territories to place control cubes into, but have the player-characters actually do point-to-point movement along the edges of the territories, because it means whatever position your character is in you have a choice about where to “tag” into.
Kitbashing can be a useful to help designers get around the bad habits we develop (I’m looking at everyone who posts graphic design questions on designers forums, about beautiful cards for games which may or may not deserve to see the light of day!)
When I worked in videogames we used to separate our systems and mechanics design from “content” design (i.e. level design, items, characters etc.).
Content design in tabletop is stuff like “we need x of these cards” or “the board needs to have x areas/be shaped like this”, and it can be seductive to jump into it too early because it’s more satisfaction for less work than fixing whatever the core issues of your game are.
That’s why kit-bashing like this example is a really good way to avoid getting bogged down in premature content design. You don’t need 120 different cards to see if your Deckbuilder engine has legs, and you certainly don’t need to custom make a map of the NYC transit system when medieval Spain will do just fine!