Grouped lists work like regular lists, except for two conditions:
- Grouped lists are always finite. Attempting to construct an infinite grouped
list will result in an infinite loop.
- Grouped lists internally represent consecutive equal elements as only one,
hence the name of /grouped lists/.
This mean that grouped lists are ideal for cases where the list has many
repetitions (like '[1,1,1,1,7,7,7,7,7,7,7,7,2,2,2,2,2]', although they might
present some deficiencies in the absent of repetitions.