Regex Tiles (a coding mini game)

Tutorial (Level 0)

Try typing . and then press Enter
The yellow lines below the tiles show what will be matched by your regex
For level 0, there is only one color of tile so you can match every character.
The regex wildcard (.) matches one of anything.
Your regex is applied with the "g" (global) flag, so it matches as many times as possible. A single period will match the entire bottom row.

There are now two colors
Your regex will only work if you match one color
Try typing one letter and pressing Enter
Every time you press Enter (or the timer expires), you get more letters
Try typing all the letters of one color, joined by |. For example, A|N|K
For letters that show up in both colors, target one of them by typing a sequence of letters that only appears in one color
You might want to match everything except certain letters. Use [^XYZ] to match everything except X, Y, or Z

Type some RegEx to match tiles
You're matching against the bottom row
Empty columns are treated as spaces
You're only allowed to match tiles of one color at a time
If you match more than one color, your match is invalid
Your regex is applied when the timer expires or when you press Enter
The longer you wait before pressing Enter, the more tiles that will be released
Your regex is applied with the "g" (global) flag so it can match multiple parts of the line

Tips

Use . to match any character
You can match exactly one letter by typing only that letter
You can match multiple letters by joining them with pipe characters (|)
You can match everything between two letters with X.*Y (which means "X followed by anything followed by Y")

Use + to repeat a character one or more times (e.g. match aaaaaa with a+
Use * to repeat a character zero or more times (e.g. match aaaaaa or the empty string with a+
Use {n} to repeat a character n times (e.g. match aaaaaa with a{6}

[xyz] defines a character class, which means "one tile that contains either x or y or z"
Use a range within a character class (e.g. match abcd with [a-d])
Common character class ranges: A-Z, a-z, 0-9
A character class can have several ranges (e.g. match any alphanumeric with [A-Za-z0-9]
Use ^ inside square braces to negate a character class to match everything except (e.g. match efgh with [^a-d])

To match a character that usually has a special meaning, you will need to escape that character with backslash
Use \X to escape some character X (e.g. match $ with \$)