diff --git a/12_union/main.v b/12_union/main.v
new file mode 100644
index 0000000..3006bc3
--- /dev/null
+++ b/12_union/main.v
@@ -0,0 +1,41 @@
+struct Rgba32_Component{
+	r u8
+	g u8
+	b u8
+	a u8
+}
+
+union Rgba32{
+	Rgba32_Component
+	mut:
+		value u32
+}
+
+pub fn main(){
+	
+	clr1 := Rgba32{
+		value: 0x008811FF
+	}
+
+	clr2 := Rgba32{
+		Rgba32_Component: Rgba32_Component{
+			a: 128
+		}
+	}
+
+	white := Rgba32{
+		Rgba32_Component : Rgba32_Component{
+			r: 255
+			g: 255
+			b: 255
+		}
+	}
+
+	sz := sizeof(Rgba32)
+
+	unsafe{ 
+		println('Size: ${sz}B,clr1.b: ${clr1.b},clr2.b: ${clr2.b}')
+		white.value = 0xFFFFF
+		println("RED ${white.r} | GREEN ${white.g} | BLUE ${white.b} | VALUE ${white.value}")
+	}
+}
\ No newline at end of file
diff --git a/13_functions/func.v b/13_functions/func.v
new file mode 100644
index 0000000..fb242bd
--- /dev/null
+++ b/13_functions/func.v
@@ -0,0 +1,30 @@
+struct User{
+	name string
+mut:
+	is_registered bool
+}
+
+fn (mut user User) register(){
+	user.is_registered = true
+}
+
+
+fn multiply_by_2(mut arr[] int){
+	for i in 0..arr.len{
+		arr[i] *= 2
+	}
+}
+
+pub fn main(){
+	
+	mut user := User{}
+	
+	println(user.is_registered)
+	user.register()
+	println(user.is_registered)
+
+	mut nums := [1,2,3]
+	multiply_by_2(mut nums)
+	println(nums)
+	
+}
\ No newline at end of file
diff --git a/13_functions/variable_number.v b/13_functions/variable_number.v
new file mode 100644
index 0000000..4314fe1
--- /dev/null
+++ b/13_functions/variable_number.v
@@ -0,0 +1,24 @@
+fn sum(a ...int) int{
+
+	mut total := 0
+
+	for x in a{
+		total += x
+	}
+
+	return total
+}
+
+pub fn main(){
+	println(sum())
+	println(sum(2,1))
+	println(sum(2,3,5,3))
+	println(sum(1))
+
+	a := [2,3,4]
+	println(sum(...a))
+
+	b := [4,5,6]
+	println(sum(...b))
+	
+}
\ No newline at end of file