Add README.

Author: ilopX

patterns/flyweight/conceptual/README.md

@@ -0,0 +1,50 @@
+# Flyweight Pattern
+Flyweight is a structural design pattern that lets you fit more objects into the available amount of
+ RAM by sharing common parts of state between multiple objects instead of keeping all of the data in
+  each object.
+
+Tutorial: [here](https://refactoring.guru/design-patterns/flyweight).
+
+### Conceptual Diagram:
+![Flyweight Pattern Diagram](https://user-images.githubusercontent.com/8049534/174476638-007f3179-495f-499d-8f35-e33956d4890b.png)
+
+### Client code:
+```dart
+void main() {
+  final factory = FlyweightFactory();
+
+  final one = factory.create('one');
+  one.draw();
+
+  final ONE = factory.create('ONE');
+  ONE.draw();
+
+  final OnE = factory.create('OnE');
+  OnE.draw();
+
+  final two = factory.create('two');
+  two.draw();
+
+  final Two = factory.create('Two');
+  Two.draw();
+}
+```
+
+### Output:
+```
+Flyweight(
+	localParam: "one", shareParam: (61, "b", 0.19)
+)
+Flyweight(
+	localParam: "ONE", shareParam: (61, "b", 0.19)
+)
+Flyweight(
+	localParam: "OnE", shareParam: (61, "b", 0.19)
+)
+Flyweight(
+	localParam: "two", shareParam: (53, "e", 0.55)
+)
+Flyweight(
+	localParam: "Two", shareParam: (53, "e", 0.55)
+)
+```