[Demo] Script to generate cascading select CSVs

[cooperka]

1. Modify NUM_LETTERS as needed
2. python3 gen-csv.py
3. Now you have a new file choices-NUM.csv
4. You can then import this CSV file into Google Sheets (like this one) and export XLS

Examples of how many CSV items will be generated for a given number of letters:

Items per cascade	Total items
3	120
4	340
6	1554
8	4680
10	11110
12	22620
14	41370
16	69904
18	111150
20	168420

Example choices generated with 3 letters:

a
b
c
aa
ab
ac
ba
bb
bc
ca
cb
cc
aaa
aab
...
cccb
cccc

(120 total items)