diff --git a/021-pointers/pointers.go b/020-pointers/pointers.go
similarity index 100%
rename from 021-pointers/pointers.go
rename to 020-pointers/pointers.go
diff --git a/020-recover/recover.go b/020-recover/recover.go
deleted file mode 100644
index 32094af..0000000
--- a/020-recover/recover.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// ## Recover
-
-package main
-
-import "fmt"
-
-func main() {
-    defer func() {    
-        fmt.Println("Preparing for trouble...\n")
-    }()
-    panic("Trouble!")
-}
diff --git a/022-new/new.go b/021-new/new.go
similarity index 100%
rename from 022-new/new.go
rename to 021-new/new.go
diff --git a/023-structs/structs.go b/022-structs/structs.go
similarity index 92%
rename from 023-structs/structs.go
rename to 022-structs/structs.go
index 5b04ffd..449860a 100644
--- a/023-structs/structs.go
+++ b/022-structs/structs.go
@@ -20,3 +20,5 @@ func main() {
 	cOrdered := Circle{1, 2, 5}
 	fmt.Println(cOrdered)
 }
+
+// todo: add field access
diff --git a/025-methods/methods.go b/023-methods/methods.go
similarity index 100%
rename from 025-methods/methods.go
rename to 023-methods/methods.go
diff --git a/026-embedding/embedding.go b/024-embedding/embedding.go
similarity index 100%
rename from 026-embedding/embedding.go
rename to 024-embedding/embedding.go
diff --git a/024-struct-fields/struct-fields.go b/024-struct-fields/struct-fields.go
deleted file mode 100644
index 6a59480..0000000
--- a/024-struct-fields/struct-fields.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// ## Struct Fields
-
-package main
-
-import "fmt"
-
-type Circle struct {
-	x, y, r int
-}
-
-func main() {
-	c := Circle{x: 1, y: 2, r: 5}
-	fmt.Println(c.x, c.y, c.r)
-	c.x = 10
-	c.y = 5
-	fmt.Println(c.x, c.y, c.r)
-}
diff --git a/027-interfaces/interfaces.go b/025-interfaces/interfaces.go
similarity index 100%
rename from 027-interfaces/interfaces.go
rename to 025-interfaces/interfaces.go
diff --git a/029-errors/errors.go b/026-errors/errors.go
similarity index 100%
rename from 029-errors/errors.go
rename to 026-errors/errors.go
diff --git a/028-ok-guards/ok-guards.go b/027-ok-guards/ok-guards.go
similarity index 87%
rename from 028-ok-guards/ok-guards.go
rename to 027-ok-guards/ok-guards.go
index e0ad577..6e5b577 100644
--- a/028-ok-guards/ok-guards.go
+++ b/027-ok-guards/ok-guards.go
@@ -18,3 +18,5 @@ func main() {
 	    fmt.Println(name)
 	}
 }
+
+// todo: note about use with errors
diff --git a/030-goroutines/goroutines.go b/028-goroutines/goroutines.go
similarity index 100%
rename from 030-goroutines/goroutines.go
rename to 028-goroutines/goroutines.go
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similarity index 100%
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similarity index 100%
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similarity index 100%
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similarity index 100%
rename from 038-scatter-gather/081-scatter-gather.go
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similarity index 100%
rename from 039-rate-limiting/rate-limiting.go
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similarity index 100%
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diff --git a/089-http-server/http-server.go b/087-http-server/http-server.go
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diff --git a/090-https-server/https-server.go b/088-https-server/https-server.go
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diff --git a/tool/index.txt b/tool/index.txt
index b42f143..d95e12a 100644
--- a/tool/index.txt
+++ b/tool/index.txt
@@ -22,16 +22,14 @@ closures
 recursion
 defer
 panic
-recover
 pointers
 new
 structs
-struct-fields
 methods
 embedding
 interfaces
-ok-guards
 errors
+ok-guards
 ~ comments
 
 # concurrency