diff --git a/doc/core_file_system.pu b/doc/core_file_system.pu
index 3e7ff9e9df63e395e88868e5217a86e963bbd717..3249ff02df6b1b0b5364fbdb1203ce365a2ac93d 100644
--- a/doc/core_file_system.pu
+++ b/doc/core_file_system.pu
@@ -8,9 +8,9 @@ skinparam sequence {
 }
 
 participant "System" as S
-participant "Folder 3\n /A.json" as F3
-participant "Folder 2\n /B.json" as F2
-participant "Folder 1\n /A.json\n /C.json" as F1
+participant "Folder of block **B5_a**\n /A.json" as F3
+participant "Folder of block **B4**\n /B.json" as F2
+participant "Folder of block **B3**\n /A.json\n /C.json" as F1
 
 == Direct READ ==
 
diff --git a/fork.pu b/fork.pu
new file mode 100644
index 0000000000000000000000000000000000000000..7291ead10a666263a90857f827cd7c9c318ae8dc
--- /dev/null
+++ b/fork.pu
@@ -0,0 +1,19 @@
+@startuml
+
+(B5_b) as B5f #LightBlue
+(B6_b) as B6f #LightBlue
+
+skinparam usecase {
+	BackgroundColor DarkSeaGreen
+	BorderColor DarkSlateGray
+	ArrowColor Blue
+}
+
+(B3) -> (B4)
+(B4) --> (B5_a)
+(B5_a) -> (B6_a)
+(B6_a) -> (B7_a)
+(B4) -[#LightBlue]> (B5f)
+(B5f) -[#LightBlue]> (B6f)
+
+@enduml
\ No newline at end of file