Lines

//Create

ymin = room_height*3/5 //adjust as needed
ymax = room_height
spd = 7 // adjust to effect
ydiv = ymax-ymin
nlines = 6

var I;
for (I=1, I<=nlines, I++)
{
 ydv[I] = (I / nlines) * ydiv
}

//draw
draw_set_color(c_lime) //c_green?
var I;
for (I=1, I<=nlines, I++)
{
 ydv[I] = (ydv[I]+spd) mod ydiv
draw_set_alpha(ydv[I]/ydiv)
draw_line(0, ymin+ydv[I], room_width, ymin+ydv[I])
}