function ret=checkob(blx, bly, trx, trty)
global robot
hit=0
if(robot.blx >=blx & robot.bly >= bly & robot.blx <= trx & robot.bly <= trty)
	hit=1  
end
if(robot.trx >=blx & robot.trty >= bly & robot.trx <= trx & robot.trty <= trty) 
   hit=1
end
if(robot.blx >=blx & robot.trty >= bly & robot.blx <= trx & robot.trty <= trty) 
   hit=1
end
if(robot.trx >=blx & robot.bly >= bly & robot.trx <= trx & robot.bly <= trty) 
   hit=1
end
ret=hit

global robot
axis([0,25,0,25])
hold

ob(1)=struct('blx',5, 'bly',5, 'trx',15, 'trty',7, 'width',10, 'height',2)
ob(2)=struct('blx',5, 'bly',5, 'trx',7, 'trty',15, 'width',2, 'height',10)
ob(3)=struct('blx',5, 'bly',13, 'trx',15, 'trty',15, 'width',10, 'height',2)

ob1=rectangle('Position', [ob(1).blx, ob(1).bly, ob(1).width, ob(1).height])
ob2=rectangle('Position', [ob(2).blx, ob(2).bly, ob(2).width, ob(2).height])
ob3=rectangle('Position', [ob(3).blx, ob(3).bly, ob(3).width, ob(3).height])

robot=struct('xpos', 14, 'ypos', 3, 'blx', 13.5, 'bly', 2.5, 'trx', 14.5, 'trty', 3.5)
target=struct('xpos', 9, 'ypos', 11)

r = plot(robot.xpos,robot.ypos,'o')
t = plot(target.xpos,target.ypos,'x')

set (r,'EraseMode', 'xor')

velocity = 0.1

hittarget = 0

while (hittarget == 0)
   
  drawnow
  vx = target.xpos - robot.xpos
  vy = target.ypos - robot.ypos

  if ((vx >= -0.1) & (vx <= 0.1) & (vy>=-0.1) & (vy <= 0.1))
    hittarget = 1
  else
    unitconst = sqrt(vx^2 + vy^2)
    uvx = vx / unitconst
    uvy = vy / unitconst

    robot.xpos = robot.xpos + (uvx * velocity)
    robot.ypos = robot.ypos + (uvy * velocity)
    robot.blx = robot.xpos - .5
    robot.bly = robot.ypos - .5
    robot.trx = robot.xpos + .5
    robot.trty = robot.ypos + .5
    
    hit1=checkob(ob(1).blx, ob(1).bly, ob(1).trx, ob(1).trty)
    hit2=checkob(ob(2).blx, ob(2).bly, ob(2).trx, ob(2).trty)
    hit3=checkob(ob(3).blx, ob(3).bly, ob(3).trx, ob(3).trty)
    if(hit1 == 1)
       uvx = 2
       uvy = -1
    end
     if(hit2 == 1)
       uvx = 2
       uvy = 1
    end
     if(hit3 == 1)
       uvx = 2
       uvy = -1
    end
    robot.xpos = robot.xpos + (uvx * velocity)
    robot.ypos = robot.ypos + (uvy * velocity)
    robot.blx = robot.xpos - .5
    robot.bly = robot.ypos - .5
    robot.trx = robot.xpos + .5
    robot.trty = robot.ypos + .5
	 set(r,'XData',robot.xpos,'YData',robot.ypos)
 	 end
end