A block is a collection of static text and elements, and components, derived from a component template. In the
template, a block is demarcated using the <t:block> or <t:parameter> elements. The interface defines no
methods, but the provided implementations of Block are capable of rendering their contents on demand.
Tapestry includes coercions from String to Renderable and Renderable to Block. This means that components that take Block parameters may be bound to
literal strings, to arbitrary numbers (or other objects, with the expectation that they will be converted to
strings), or to renderable objects such as components.