Added 20-minute 1501.
Added 20-minute 1501.

informatimago/lisp,GitoriousLispBackup/com-informatimago,informatimago/lisp,informatimago/lisp,informatimago/lisp,GitoriousLispBackup/com-informatimago,informatimago/lisp,GitoriousLispBackup/com-informatimago,informatimago/lisp,informatimago/lisp,GitoriousLispBackup/com-informatimago,GitoriousLispBackup/com-informatimago,GitoriousLispBackup/com-informatimago