Landing+a+plane

Specification
Write a program which shows a plane moving from left to right on the screen. When it reaches the right hand side it should drop a bit further down the screen and again fly from left to right. This process should be repeated until the plane reaches the bottom of the screen.

Program
Change the main sprite to a plane

Now enter the program

Extension
1. Change the program so that it shows the plane taking off and going higher up the screen.

2. Create a variable called Altitude which should be displayed. The altitude should be zero when the plane is at the lowest level and increase by 1000 every time the plane gets a level higher.