We've created several templates to extend the default concrete5 blocks. While we've only looked at the page list, content, guestbook, and slideshow block, the procedure is the same for every block you can find, as well as for blocks downloaded from the marketplace.
While templates are very easy to create, they sometimes lack functionality. In the previous examples you might have seen some values we had to add statically to a JavaScript file. This is one problem you might run into with templates; it's just a template, there's no way to change the block edit interface from a template. If you wanted to change values such as the dimensions of the pictures in a gallery, you'd have to create your own block, exactly what we're going to do in Chapter 8, Creating Your Own Add-on Block.
You can find all the templates from this chapter in the accompanying ZIP file, so extract it to blocks and all templates will be available.
But luckily, concrete5 is not restricted to custom templates; you can...