README.md in whirled_peas-0.4.0 vs README.md in whirled_peas-0.4.1

@@ -22,13 +22,13 @@
 
 ## Usage
 
 A Whirled Peas application consists of the following pieces
 
-1. [REQUIRED] The driver, which emits lightweight frame events
-1. [REQUIRED] The main template factory, which builds templates to convert frame events from the driver into terminal graphics
-1. [OPTIONAL] A loading screen template factory, which is used while content is loading
+- The driver (required) - the code that is to be visualized, it emits lightweight frame events through a producer
+- The main template factory (required) - builds templates to convert frame events from the driver into terminal graphics
+- A loading screen template factory (optional) - builds templates to display while content is loading
 
 These pieces are configured as following
 
 ```ruby
 # visualize.rb
@@ -37,20 +37,20 @@
 class TemplateFactory
   def build(frame, args)
     WhirledPeas.template do |body|
       body.add_box('Title') do |_, settings|
         settings.underline = true
-        "Hello #{args['name']}"
+        "Hello #{args[:name]}"
       end
       # ...
     end
   end
 end
 
 class Driver
   def start(producer)
-    producer.send_frame('starting', args: { 'name' => 'World' })
+    producer.send_frame('starting', args: { name: 'World' })
     # ...
   end
 end
 
 WhirledPeas.configure do |config|
@@ -65,11 +65,11 @@
 $ whirled_peas start visualize.rb
 ```
 
 The optional loading screen can be configured like
 
-````ruby
+```ruby
 class LoadingTemplateFactory
   def build
     WhirledPeas.template do |t|
       t.add_box('Loading') do |box, settings|
         settings.set_margin(top: 15)
@@ -96,23 +96,25 @@
 #
 # @param producer [Producer] frame producer that sends events to the UI
 def start(producer)
   # application code here
 end
-````
+```
 
 The producer provides a single method
 
 ```ruby
 # Send frame events to the UI
 #
 # @param name [String] application defined name for the frame. The template factory will be provided this name
 # @param duration [Number] time in seconds this frame should be displayed for (defaults to 1 frame)
-# @param args [Hash] key value pairs to send as arguments to the template factory
+# @param args [Hash<Symbol, Object>] key value pairs to send as arguments to the template factory
 def send_frame(name, duration:, args:)
   # implementation
 end
 ```
+
+**IMPORTANT**: the keys for arguments must be symbols.
 
 #### Example
 
 Simple application that loads a set of numbers and looks for a pair that adds up to 1,000