> To be able to draw programs that look visually appealing themselves, such that someone would want to put a frame around them and hang them on the wall.

I've done that with the predecessor function in lambda diagram form:

    ┬──────────
    ┼─────┬────
    ┼─────┼─┬──
    │ ──┬─┼ ┼ ┬
    │ ┬─┼─┼ │ │
    │ │ ├─┘ │ │
    │ ├─┘   │ │
    └─┤     │ │
      └─────┤ │
            └─┘

Lambda diagrams [1] are just a graphical output format for the pure lambda calculus though, and not a 2D programming language like Λ-2D.

[1] https://tromp.github.io/cl/diagrams.html