diff --git a/TODO.md b/TODO.md
index dce6e03a..251fc7a4 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,5 +1,3 @@
-`createTrivialTypes`
-
 `Type` should be type instead of class
 
 [maybe] quit using `def/` and `defs/`
diff --git a/docs/articles/design-of-new-syntax.md b/docs/articles/design-of-new-syntax.md
index 15c1c0bc..61975ad5 100644
--- a/docs/articles/design-of-new-syntax.md
+++ b/docs/articles/design-of-new-syntax.md
@@ -85,7 +85,7 @@ end
 We use a simple type system like Haskell (for now).
 
 ```inet
-defnode sole -- !Sole end
+defnode sole -- !Trivial end
 
 defnode null -- !List('a) end
 
diff --git a/src/lang/mod/builtInOperators.ts b/src/lang/mod/builtInOperators.ts
index 6d1b9278..b6008d29 100644
--- a/src/lang/mod/builtInOperators.ts
+++ b/src/lang/mod/builtInOperators.ts
@@ -2,7 +2,7 @@ import { Mod } from "."
 import * as Defs from "../defs"
 import { Port } from "../graph"
 import { netConnect } from "../graph/netConnect"
-import { buildTypes } from "../types"
+import { createTrivialTypes } from "../type"
 
 export function builtInOperators(mod: Mod): void {
   mod.defineOperator("swap", (net) => {
@@ -25,13 +25,8 @@ export function builtInOperators(mod: Mod): void {
   })
 
   mod.defineOperator("wire", (net) => {
-    const def = new Defs.NodeDef(
-      mod,
-      "Cons",
-      "wire",
-      [],
-      buildTypes(["Any", "Any"]),
-    )
+    const def = new Defs.NodeDef(mod, "Cons", "wire", [], createTrivialTypes(2))
+
     const node = def.build()
 
     net.portStack.push(...node.output)
diff --git a/src/lang/stmts/DefconsStmt.ts b/src/lang/stmts/DefconsStmt.ts
index 156c6807..4feed09a 100644
--- a/src/lang/stmts/DefconsStmt.ts
+++ b/src/lang/stmts/DefconsStmt.ts
@@ -2,7 +2,7 @@ import * as Defs from "../defs"
 import { Mod } from "../mod"
 import { Span } from "../span"
 import { Stmt } from "../stmt"
-import { buildTypes } from "../types"
+import { createTrivialTypes } from "../type"
 
 export class DefconsStmt extends Stmt {
   constructor(
@@ -21,8 +21,8 @@ export class DefconsStmt extends Stmt {
         mod,
         "Cons",
         this.name,
-        buildTypes(Array(this.inputArity).fill("Any")),
-        buildTypes(Array(this.outputArity).fill("Any")),
+        createTrivialTypes(this.inputArity),
+        createTrivialTypes(this.outputArity),
       ),
     )
   }
diff --git a/src/lang/stmts/DefelimStmt.ts b/src/lang/stmts/DefelimStmt.ts
index dfbba155..bd5d4e2f 100644
--- a/src/lang/stmts/DefelimStmt.ts
+++ b/src/lang/stmts/DefelimStmt.ts
@@ -2,7 +2,7 @@ import * as Defs from "../defs"
 import { Mod } from "../mod"
 import { Span } from "../span"
 import { Stmt } from "../stmt"
-import { buildTypes } from "../types"
+import { createTrivialTypes } from "../type"
 
 export class DefelimStmt extends Stmt {
   constructor(
@@ -21,8 +21,8 @@ export class DefelimStmt extends Stmt {
         mod,
         "Elim",
         this.name,
-        buildTypes(Array(this.inputArity).fill("Any")),
-        buildTypes(Array(this.outputArity).fill("Any")),
+        createTrivialTypes(this.inputArity),
+        createTrivialTypes(this.outputArity),
       ),
     )
   }
diff --git a/src/lang/type/Type.ts b/src/lang/type/Type.ts
index 4105ea34..522e40a9 100644
--- a/src/lang/type/Type.ts
+++ b/src/lang/type/Type.ts
@@ -1,7 +1 @@
-export abstract class Type {
-  abstract format(): string
-
-  isPrincipal(): boolean {
-    return false
-  }
-}
+export type Type = {}
diff --git a/src/lang/type/createTrivialTypes.ts b/src/lang/type/createTrivialTypes.ts
new file mode 100644
index 00000000..54e5b9f4
--- /dev/null
+++ b/src/lang/type/createTrivialTypes.ts
@@ -0,0 +1,5 @@
+import { Type } from "./Type"
+
+export function createTrivialTypes(arity: number): Array<Type> {
+  return Array(arity).fill({})
+}
diff --git a/src/lang/type/index.ts b/src/lang/type/index.ts
index 586bcbda..af72814f 100644
--- a/src/lang/type/index.ts
+++ b/src/lang/type/index.ts
@@ -1 +1,2 @@
 export * from "./Type"
+export * from "./createTrivialTypes"
diff --git a/src/lang/types/AtomType.ts b/src/lang/types/AtomType.ts
deleted file mode 100644
index f56e029a..00000000
--- a/src/lang/types/AtomType.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { Type } from "../type"
-
-export class AtomType extends Type {
-  name: string
-
-  constructor(name: string) {
-    super()
-    this.name = name
-  }
-
-  format(): string {
-    return this.name
-  }
-}
diff --git a/src/lang/types/TypeBuilder.ts b/src/lang/types/TypeBuilder.ts
deleted file mode 100644
index 54d764d4..00000000
--- a/src/lang/types/TypeBuilder.ts
+++ /dev/null
@@ -1,34 +0,0 @@
-import * as Types from "."
-import { Type } from "../type"
-
-export class TypeBuilder {
-  words: Array<string>
-
-  constructor(words: Array<string>) {
-    this.words = words
-  }
-
-  build(): Array<Type> {
-    const types: Array<Type> = []
-    for (const word of this.words) {
-      if (word === "*") {
-        const t = types.pop()
-        if (t === undefined) {
-          throw new Error(
-            [
-              `Fail to build type,`,
-              `I expect a type on the stack when applying *`,
-              `  words: ${this.words}`,
-            ].join("\n"),
-          )
-        } else {
-          throw new Error()
-        }
-      } else {
-        types.push(new Types.AtomType(word))
-      }
-    }
-
-    return types
-  }
-}
diff --git a/src/lang/types/buildTypes.ts b/src/lang/types/buildTypes.ts
deleted file mode 100644
index 10fcdd6e..00000000
--- a/src/lang/types/buildTypes.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-import { TypeBuilder } from "."
-import { Type } from "../type"
-
-export function buildTypes(words: Array<string>): Array<Type> {
-  return new TypeBuilder(words).build()
-}
diff --git a/src/lang/types/index.ts b/src/lang/types/index.ts
deleted file mode 100644
index 786b20ab..00000000
--- a/src/lang/types/index.ts
+++ /dev/null
@@ -1,5 +0,0 @@
-// organize-imports-ignore
-
-export * from "./AtomType"
-export * from "./TypeBuilder"
-export * from "./buildTypes"