Lambda the Ultimate

I've just begun reading Whitehead and Russell's "Principia Mathematica" available here and was surprised to find on page 9 a nice readable alternative to parentheses for grouping.

Each operator is preceded and/or succeeded by some dots written as colons and periods. The more dots an operator has, the lower precedence it has. To take one of their examples (page 10),
p -> q .->. q -> r :->. p -> r
means
((p -> q) -> (q -> r)) -> (p -> r)

I find the dot version more readable and easier to type than the parentheses version. I'm curious if anyone here knows of other alternatives to parentheses for grouping. Prefix and postfix we've all heard of here, but do you have less well known ones? Hideous or beautiful I'd love to see them! Have any been tried in programming languages?

Prompted by Z-bo's question of what is there to gripe about CSS, I thought I'd point out the Clutter toolkit:

Clutter is an open source software library for creating fast, visually rich, portable and animated graphical user interfaces.

Clutter uses OpenGL (and optionally OpenGL|ES for use on Mobile and embedded platforms) for rendering but with an API which hides the underlying GL complexity from the developer. The Clutter API is intended to be easy to use, efficient and flexible.

Similar to Bling, it explores how GPU abstractions should be exposed to UI layout designers. I think there will be a lot of turmoil in this space over the next few years. Some related projects of interest are PixelBlender (with its integration into Flex 4) and similar projects in the Silverlight community. Another approach is to try to not change anything, as in a new GPU-accelerated Firefox branch. The only comparable approach I know of in the PL space is Conal Elliott's Vertigo, but that was not really about structured UI.

Edit: link fixed.

Edit 2: two big motivations here 1) performance on mobile devices and 2) enabling new types of UIs, such as physically realistic ones