The underlying data structure of MISC is the associative array or map. That is, unlike LISP (+ 3 4) is not a list, it is a map which can be written as [0:+ 1:3 2:4]. Everything in MISC is a map.
This [key:value ...] syntax is the foundation for everything. Any values without keys are numbered from 0 upwards in the order they are written, thus [+ 3 4] is equivalent to [0:+ 1:3 2:4]. Maps are unordered therefore this expression could also be written as [1:3 0:+ 2:4].
To enter data, that is not evaluated, in MISC prefix a map with a single quote '. For example, '[apples:100 oranges:23].
Try some expressions: