Part $2$: Open the "house" project from within BlueJ. $($You will use this for parts $2,3,$ and

$4.)$

o Create an instance of "Picture". Invoke the "draw" method and then the other

methods.

o How do you think "Picture" draws the picture?

o Look at the pop$-$up menu for class "Picture". Select "Open editor". Look at the

code.

o In the code, find where the picture is drawn and change the sun from yellow to

blue.

$$ Part $3$: Take your solution to part $2,$ and rename $$sun$$ to $$moon$.$ Make the moon blue

and move it a little further to the right of the picture. $($Aside: You can really put the moon

anywhere you like, as long as you get the desired effect. We found that unless we moved

the moon a bit, the added circle ended up covering part of the roof of the house, which

looked strange!$)$ Now you are going to add a new method "moonPhases" to model the

different phases of the moon. Our model of the moon phases is to be implemented by

moving another $($new$)$ circle across our blue moon from right to left, to get an effect

similar to the phases of the moon $($in super$-$fast motion$).$ Think about what colour this

new circle should be$.$ Check that all the other methods still work properly. $($This is called

"regression" testing.$)$

$$ Part $4$: Start with your solution to part $3.$ The moon is normally only visible at night, i$.$e$.$

when it is dark. Figure out how to change the background colour of your picture from

white to black. $($Hint: This is not set in the $$Picture$$ class.$)$ Then redo part $3.$ Again, do

your regression testing.