program fly_anim
      write(*,*)'Vx?'
      read(*,*)vx
      write(*,*)'Vy?'
      read(*,*)vy
      i_dummy=pgopen('/xwin')
      xmin=0
      xmax=10
      ymin=0
      ymax=10
      call pgenv(xmin,xmax,ymin,ymax,1,0)
      x=0
      y=2
      xold=x
      yold=y
      ax=0
      ay=-9.8
      dt=0.0001
      do while (y>0)
        vx=vx+ax*dt
        vy=vy+ay*dt
        x=x+vx*dt
        y=y+vy*dt
        call pgsci(0)
        call pgcirc(xold,yold,0.02)
        call pgsci(1)
        call pgcirc(x,y,0.02)
        xold=x
        yold=y
      end do
      write(*,*)'Hight=',y,'Distance=',x
      call pgclos
      end