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 {@link org.apache.tapestry5.Renderable} and {@link org.apache.tapestry5.Renderable} to Block. This means that components that take Block parameters may be bound toliteral strings, to arbitrary numbers (or other objects, with the expectation that they will be converted to strings), or to renderable objects such as components.