recursiveDefintion example on 7.1.2:
<UIKeyboardImpl: frame = (0 0; 320 216);>
| <UIKeyboardLayoutStar: frame = (0 0; 320 216);>
| | <UIKBBackgroundView: frame = (0 0; 320 216);>
| | <UIKBKeyplaneView: frame = (0 0; 320 216);>
| | | <UIKBKeyView: frame = (1 119; 40 42);>
| | | <UIKBKeyView: frame = (279 119; 40 42);>
| | | <UIKBKeyView: frame = (1 173; 38 42);>
| | | <UIKBKeyView: frame = (41 173; 38 42);>
| | | <UIKBKeyView: frame = (81 173; 158 42);>
| | | <UIKBKeyView: frame = (241 173; 78 42);>
| | <UIKBDimmingView: frame = (0 0; 320 216);>