Euler Angles

Euler angles allow you to specify any 3D rotation with just 3 values, these values are as follows:

Pitch

Up and down (i.e. looking up and down)

Yaw

Side to side (i.e. looking left and right)

Roll

Tilting (i.e. tilting your head from side to side)

References

Math for Game Developers - Mouse Control (Euler Angles) Video on YouTube

App Icons and iTunes Icons for iOS Apps

You can change what App Icon your iOS App is going to have through the assets catalog. You will need to create quite a few different sizes and I've found the best way to do this is to make the biggest one and resize it accordingly, but where do all these different sizes go? First you will need to enable all the sizes you need, by clicking on the AppIcon asset and finding the following pane:



You can enable/disable these as appropriate for your app, and you should end up with an asset catalog that looks like this:



The above image should tell you what image sizes you will need for your App icons, and where they need to be placed in the catalog.

References

Apple Developer