diff --git a/gomore/05_fan_out/fan_out_in.go b/gomore/05_fan_out/fan_out_in.go
new file mode 100644
index 0000000..88e65d0
--- /dev/null
+++ b/gomore/05_fan_out/fan_out_in.go
@@ -0,0 +1,276 @@
+package fanout
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"sync"
+	"time"
+)
+
+func run() {
+	ctx, cancelFunc := context.WithCancel(context.Background())
+	defer cancelFunc()
+	var errcList []chan error
+
+	//	res := fanin(fanout(generateNumbers(ctx), squareNumbers))
+
+	nChan, errc, err := generateNumbers(ctx)
+	if err != nil {
+		log.Fatal(err)
+	}
+	errcList = append(errcList, errc)
+
+	fChanl, errcl, err := fanout(ctx, nChan, squareNumbers)
+	errcList = append(errcList, errcl...)
+
+	res, errRes, err := fanin(fChanl, errcl)
+
+	go func() {
+		for {
+			select {
+			case r := <-res:
+				v, ok := r.(int)
+				if !ok {
+					// TODO
+					_ = ok
+				}
+				fmt.Println(v)
+			case e := <-errRes:
+				fmt.Println(e)
+			}
+		}
+	}()
+
+	fmt.Println("finished")
+	time.Sleep(10 * time.Duration(time.Second))
+}
+
+type Op func(context.Context, chan interface{}) (chan interface{}, chan error, error)
+
+func generateNumbers(ctx context.Context) (chan interface{}, chan error, error) {
+	fmt.Println("generateNumbers called")
+	out := make(chan interface{}, 100)
+	errc := make(chan error, 100)
+
+	go func() {
+		defer close(out)
+		defer close(errc)
+
+		for i := 0; i < 10; i++ {
+			fmt.Println("gen: ", i)
+			out <- i
+		}
+	}()
+
+	return out, errc, nil
+}
+
+func fanout(ctx context.Context, in chan interface{}, fct Op) ([]chan interface{}, []chan error, error) {
+	fmt.Println("fanout called")
+	var out []chan interface{}
+	var errcl []chan error
+
+	for i := 0; i < 5; i++ {
+		res, errc, err := fct(ctx, in)
+		// Todo: manage error
+		_ = err
+		out = append(out, res)
+		errcl = append(errcl, errc)
+	}
+
+	return out, errcl, nil
+}
+
+func squareNumbers(ctx context.Context, in chan interface{}) (chan interface{}, chan error, error) {
+	fmt.Println("squareNumbers called")
+	out := make(chan interface{}, 100)
+	errc := make(chan error, 100)
+
+	go func() {
+		for v := range in {
+			num, _ := v.(int)
+
+			squared := num * num
+
+			select {
+			case out <- squared:
+			case <-ctx.Done():
+				fmt.Println("ctx done")
+				return
+			}
+		}
+		close(out)
+	}()
+
+	return out, errc, nil
+}
+
+func fanin(ins []chan interface{}, errcl []chan error) (chan interface{}, chan error, error) {
+	fmt.Println("fanin called")
+	out := make(chan interface{}, 100)
+	errcout := make(chan error, 100)
+	var waitgroup sync.WaitGroup
+
+	length := len(ins) + len(errcl)
+	waitgroup.Add(length)
+
+	for _, v := range ins {
+		go func(w chan interface{}) {
+			for val := range w {
+				out <- val
+			}
+			waitgroup.Done()
+		}(v)
+	}
+
+	for _, e := range errcl {
+		go func(errc chan error) {
+			for v := range errc {
+				errcout <- v
+			}
+			waitgroup.Done()
+		}(e)
+	}
+
+	go func() {
+		waitgroup.Wait()
+		close(out)
+		close(errcout)
+	}()
+
+	return out, errcout, nil
+}
+func main() {
+	ctx, cancelFunc := context.WithCancel(context.Background())
+	defer cancelFunc()
+	var errcList []chan error
+
+	//	res := fanin(fanout(generateNumbers(ctx), squareNumbers))
+
+	nChan, errc, err := generateNumbers(ctx)
+	if err != nil {
+		log.Fatal(err)
+	}
+	errcList = append(errcList, errc)
+
+	fChanl, errcl, err := fanout(ctx, nChan, squareNumbers)
+	errcList = append(errcList, errcl...)
+
+	res, errRes, err := fanin(fChanl, errcl)
+
+	go func() {
+		for {
+			select {
+			case r := <-res:
+				v, ok := r.(int)
+				if !ok {
+					// TODO
+					_ = ok
+				}
+				fmt.Println(v)
+			case e := <-errRes:
+				fmt.Println(e)
+			}
+		}
+	}()
+
+	fmt.Println("finished")
+	time.Sleep(10 * time.Duration(time.Second))
+}
+
+type Op func(context.Context, chan interface{}) (chan interface{}, chan error, error)
+
+func generateNumbers(ctx context.Context) (chan interface{}, chan error, error) {
+	fmt.Println("generateNumbers called")
+	out := make(chan interface{}, 100)
+	errc := make(chan error, 100)
+
+	go func() {
+		defer close(out)
+		defer close(errc)
+
+		for i := 0; i < 10; i++ {
+			fmt.Println("gen: ", i)
+			out <- i
+		}
+	}()
+
+	return out, errc, nil
+}
+
+func fanout(ctx context.Context, in chan interface{}, fct Op) ([]chan interface{}, []chan error, error) {
+	fmt.Println("fanout called")
+	var out []chan interface{}
+	var errcl []chan error
+
+	for i := 0; i < 5; i++ {
+		res, errc, err := fct(ctx, in)
+		// Todo: manage error
+		_ = err
+		out = append(out, res)
+		errcl = append(errcl, errc)
+	}
+
+	return out, errcl, nil
+}
+
+func squareNumbers(ctx context.Context, in chan interface{}) (chan interface{}, chan error, error) {
+	fmt.Println("squareNumbers called")
+	out := make(chan interface{}, 100)
+	errc := make(chan error, 100)
+
+	go func() {
+		for v := range in {
+			num, _ := v.(int)
+
+			squared := num * num
+
+			select {
+			case out <- squared:
+			case <-ctx.Done():
+				fmt.Println("ctx done")
+				return
+			}
+		}
+		close(out)
+	}()
+
+	return out, errc, nil
+}
+
+func fanin(ins []chan interface{}, errcl []chan error) (chan interface{}, chan error, error) {
+	fmt.Println("fanin called")
+	out := make(chan interface{}, 100)
+	errcout := make(chan error, 100)
+	var waitgroup sync.WaitGroup
+
+	length := len(ins) + len(errcl)
+	waitgroup.Add(length)
+
+	for _, v := range ins {
+		go func(w chan interface{}) {
+			for val := range w {
+				out <- val
+			}
+			waitgroup.Done()
+		}(v)
+	}
+
+	for _, e := range errcl {
+		go func(errc chan error) {
+			for v := range errc {
+				errcout <- v
+			}
+			waitgroup.Done()
+		}(e)
+	}
+
+	go func() {
+		waitgroup.Wait()
+		close(out)
+		close(errcout)
+	}()
+
+	return out, errcout, nil
+}