A simple VCCC2021 entry.

Author:   KeyJ <keyj@emphy.de>
Platform: Sinclair ZX Spectrum (any version)
Language: Sinclair BASIC
Length:   It's complicated!
          -  76 bytes (pure BASIC tokens)
          - 118 bytes (BASIC source in ASCII)
          - 113 bytes (BASIC program image in memory)
          - 138 bytes (.tap file with header)
Run with: fuse tree2.tap

This is an almost trivial implementation; the only noteworthy thing
about it is the misuse of a string variable as data storage, because
Sinclair BASIC stores both the floating-point and text representation
of numerical constants in program memory, which makes the .tap file
larger than it would need to be when using e.g. a DATA statement.

                                                                 -- KeyJ