"song09". . "song09(t)". . "chs2". . "chs2(t)*chase(t, names=back, ontime=1, offset=.08, random=1)". . "full". . "full(t)". . . . . . . . . "blue". . "blue(t)". . "t1". . "t1(t)". . "chs1". . "chs1(t)*chase(t, names=colors, ontime=.3, offset=.1)". . "st1". . "stack(st1(t), names=back2)". .