diff --git a/014-functions/functions.go b/013-functions/functions.go
similarity index 100%
rename from 014-functions/functions.go
rename to 013-functions/functions.go
diff --git a/013-nesting/nesting.go b/013-nesting/nesting.go
deleted file mode 100644
index d910df8..0000000
--- a/013-nesting/nesting.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// ## Nesting
-
-package main
-
-import "fmt"
-
-func main() {
-    elements := map[string]map[string]string{
-        "He": map[string]string{
-            "name":"Helium", 
-            "state":"gas",
-        },
-        "Li": map[string]string{
-            "name":"Lithium", 
-            "state":"solid",
-        },
-        "Be": map[string]string{
-            "name":"Beryllium", 
-            "state":"solid",
-        },
-    }
-
-	fmt.Println(elements)
-	fmt.Println()
-
-	li := elements["Li"]
-	fmt.Println(li)
-	fmt.Println()
-
-	fmt.Println(li["name"], li["state"])
-}
diff --git a/015-returns/returns.go b/015-multiple-return-values/multiple-returns-values.go
similarity index 82%
rename from 015-returns/returns.go
rename to 015-multiple-return-values/multiple-returns-values.go
index 1325a95..0096bb5 100644
--- a/015-returns/returns.go
+++ b/015-multiple-return-values/multiple-returns-values.go
@@ -16,7 +16,8 @@ func vals() (int, int) {
 }
 
 func main() {
-    // Use the 2 different return values from the call.
+    // Use the 2 different return values from the call,
+    // i.e. multiple assignement.
     x, y := vals()        
     fmt.Println(x)
     fmt.Println(y)
diff --git a/015-multiple-return-values/returns.sh b/015-multiple-return-values/returns.sh
new file mode 100644
index 0000000..f9bd631
--- /dev/null
+++ b/015-multiple-return-values/returns.sh
@@ -0,0 +1,3 @@
+$ go run multiple-return-values.go
+3
+7
diff --git a/015-returns/returns.sh b/015-returns/returns.sh
deleted file mode 100644
index 0a344c6..0000000
--- a/015-returns/returns.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-$ go run returns.go
-3
-7
diff --git a/016-varadic/varadic.go b/015-varadic-functions/varadic-functions.go
similarity index 100%
rename from 016-varadic/varadic.go
rename to 015-varadic-functions/varadic-functions.go
diff --git a/016-varadic/varadic.sh b/015-varadic-functions/varadic-functions.sh
similarity index 50%
rename from 016-varadic/varadic.sh
rename to 015-varadic-functions/varadic-functions.sh
index 300c303..456e1ae 100644
--- a/016-varadic/varadic.sh
+++ b/015-varadic-functions/varadic-functions.sh
@@ -1,4 +1,4 @@
-$ go run varadic.go
+$ go run varadic-functions.go
 [1 2] 3
 [1 2 3] 6
 [1 2 3 4] 10
diff --git a/017-closures/closures.go b/016-closures/closures.go
similarity index 100%
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diff --git a/088-http-server-static/http-server-static.go b/087-http-server-static/http-server-static.go
similarity index 100%
rename from 088-http-server-static/http-server-static.go
rename to 087-http-server-static/http-server-static.go
diff --git a/088-http-server-static/http-server-static.sh b/087-http-server-static/http-server-static.sh
similarity index 100%
rename from 088-http-server-static/http-server-static.sh
rename to 087-http-server-static/http-server-static.sh
diff --git a/089-http-server-status-code/http-server-status-code.go b/088-http-server-status-code/http-server-status-code.go
similarity index 100%
rename from 089-http-server-status-code/http-server-status-code.go
rename to 088-http-server-status-code/http-server-status-code.go
diff --git a/089-http-server-status-code/http-server-status-code.sh b/088-http-server-status-code/http-server-status-code.sh
similarity index 100%
rename from 089-http-server-status-code/http-server-status-code.sh
rename to 088-http-server-status-code/http-server-status-code.sh
diff --git a/090-http-server/http-server.go b/089-http-server/http-server.go
similarity index 100%
rename from 090-http-server/http-server.go
rename to 089-http-server/http-server.go
diff --git a/091-https-server/https-server.go b/090-https-server/https-server.go
similarity index 100%
rename from 091-https-server/https-server.go
rename to 090-https-server/https-server.go
diff --git a/091-https-server/https-server.sh b/090-https-server/https-server.sh
similarity index 100%
rename from 091-https-server/https-server.sh
rename to 090-https-server/https-server.sh
diff --git a/tool/index.txt b/tool/index.txt
index b09e77b..8583926 100644
--- a/tool/index.txt
+++ b/tool/index.txt
@@ -15,10 +15,9 @@ arrays
 range
 slices
 maps
-nesting
 functions
 returns
-varadic
+varadic-functions
 closures
 recursion
 defer
@@ -27,7 +26,7 @@ recover
 pointers
 new
 structs
-fields
+struct-fields
 methods
 embedding
 interfaces