Typography without the constraining flat baselines or top edges allows a beautiful variation for both a traditional or a modern feeling.
Almost any concept for a logo has probably already been used. It is the visual treatment that distinguishes various logos, a system of shapes.
A design made of only lines can be successful as long as both the lines and the gaps between are not too fine or small.
Planar shapes represent shadows with solid shapes. Silhouettes show an overall contour with solid shapes. Both techniques can make good logos.
Containment can be as shallow as putting a shape around a signature or it can be the saving grace of a good design.