setscreen ("graphics:400,400;offscreenonly")
var mx, my, mb : int
var pointx, pointy : array 1 .. 2 of int
var clicked : int
var x, y, vx, vy, grav : real := 0
var collision : boolean := false
var m, b : real
x := 200
y := 120
grav := 0.001
pointx (1) := 0
pointy (1) := 100
pointx (2) := 400
pointy (2) := 100
loop
    cls
    mousewhere (mx, my, mb)
    drawline (pointx (1), pointy (1), pointx (2), pointy (2), 7)
    drawoval (pointx (1), pointy (1), 5, 5, 7)
    drawoval (pointx (2), pointy (2), 5, 5, 7)
    drawfilloval (round (x), round (y), 10, 10, 4)
    if round (Math.Distance (pointx (1), pointy (1), mx, my)) <= 25 and mb = 1 then
        clicked := 1
    elsif round (Math.Distance (pointx (2), pointy (2), mx, my)) <= 25 and mb = 1 then
        clicked := 2
    else
        clicked := 0
    end if
    if clicked ~= 0 then
        pointx (clicked) := mx
        pointy (clicked) := my
    end if
    y -= vy
    vy += grav
    m := (pointy (1) - pointy (2)) / (pointx (1) - pointx (2))
    b := pointy (1) - m * pointx (1)
    if collision then
        x -= m
        vy := 0
        y := m * x + b
    end if
    if round (y) = m * x + b then
        collision := true
    end if
    View.Update
    exit when hasch
end loop