Merge branch 'master' into BAEL-16646-2

patterns/solid/src/main/java/com/baeldung/o/Guitar.java

@@ -0,0 +1,10 @@
+package com.baeldung.o;
+
+public class Guitar {
+
+  private String make;
+  private String model;
+  private int volume;
+
+  //Constructors, getters & setters
+}

patterns/solid/src/main/java/com/baeldung/o/SuperCoolGuitarWithFlames.java

@@ -0,0 +1,9 @@
+package com.baeldung.o;
+
+public class SuperCoolGuitarWithFlames extends Guitar {
+
+  private String flameColour;
+
+  //constructor, getters + setters
+
+}