How do I define multiple blocks in one module and include different javascript for each? In Drupal 8

I understand that to create a block I create a file in this structure:

mymodule/src/Plugin/Block/MyModuleBlock.php


If I would like to create another block for this module, or even a dozen blocks in this module, where do I define them so that they render differently and contain different javascript/css?
Use the following folder structure to create multiple custom blocks in drupal 8

-mymodule
--src
---Plugin
----Block
-----block1.php
-----block2.php
-----block3.php