I ran:
$ raco pkg install lux
Resolving "lux" via http://download.racket-lang.org/releases/6.3/catalog/
Resolving "lux" via http://pkgs.racket-lang.org
Using cached15253002841525300284739 for git://github.com/jeapostrophe/lux
Promoting lux from auto-installed to explicitly installed
$ git clone https://gitlab.com/dustyweb/racktris.git
Cloning into 'racktris'...
remote: Enumerating objects: 155, done.
remote: Counting objects: 100% (155/155), done.
remote: Compressing objects: 100% (120/120), done.
remote: Total 155 (delta 60), reused 112 (delta 34)
Receiving objects: 100% (155/155), 59.41 KiB | 0 bytes/s, done.
Resolving deltas: 100% (60/60), done.
Checking connectivity... done.
$ cd racktris
$ racket racktris.rkt
collect-garbage: contract violation
expected: (or/c 'major 'minor)
given: 'incremental
context...:
/home/nick/.racket/6.3/pkgs/lux/word.rkt:70:2: output&process-input&wait
/home/nick/.racket/6.3/pkgs/lux/word.rkt:45:0: call-with-chaos
(submod /data/nick/i/gitworking/misc/racktris/racktris.rkt main): [running body]
$