your code
// shuttle
shuttle(50,50,1000);
// mothership
mothership(500,450)
// command to move
// fuel
fuel(400,150,300)
fuel(500,250,50)
// asteroide
asteroid(400,200)
asteroid(150,200)
asteroid(100,250)
asteroid(300,400)
asteroid(400,400)
// wal
wall(450,100,450,200)
wall(250,330,250,430)
wall(100,320,100,450)
wall(300,170,300,240)
wall(400,460,400,600)
wall(450,460,450,600)
wall(550,460,550,650)
wall(300,460,300,650)
wall(300,650,550,650)
// planet
planet(300,150,"uranus")
planet(300,300,"mars")
planet(300,450,"earth")
// alien
alien(350,300,350,450)
alien(200,50,200,200)
alien(50,300,200,300)