diff --git a/src/algebra/io.js b/src/algebra/io.js
new file mode 100644
index 0000000..a5e0782
--- /dev/null
+++ b/src/algebra/io.js
@@ -0,0 +1,53 @@
+import { Algebra, Monad } from './index.js'
+
+/** @import { Fn, InferredMorphism, Morphism } from './types.js' */
+
+/** @template {Fn} T */
+export class IO extends Algebra(Monad) {
+  _effect
+
+  /**
+   * @type {T} effect
+   */
+  constructor(effect) {
+    super()
+    this._effect = effect
+  }
+
+  /**
+   * @template {Fn} T
+   * @param {T} a
+   */
+  static of(a) {
+    return new IO(() => a)
+  }
+
+  /**
+   * @param {InferredMorphism<T>} f
+   */
+  chain(f) {
+    return IO.of(() => f(this.run()).run())
+  }
+
+  /**
+   * @param {InferredMorphism<T>} f
+   */
+  map(f) {
+    return IO.of(() => f(this.run()))
+  }
+
+  /**
+   * @template {Fn} U
+   * @this {IO<T>}
+   * @param {IO<Morphism<T, U>>} other
+   * @returns {IO<U>}
+   */
+  ap(other) {
+    return IO.of(() => other.run()(this.run()))
+  }
+
+  run() {
+    return this._effect()
+  }
+}
+
diff --git a/src/algebra/list.js b/src/algebra/list.js
index 171cbd7..bc84dae 100644
--- a/src/algebra/list.js
+++ b/src/algebra/list.js
@@ -1,7 +1,7 @@
 import { Pure, Suspend } from './free.js'
 import { AlgebraWithBase, Category, Comonad, Foldable, Monoid } from './index.js'
 
-/** @import { InferredMorphism } from './types.js' */
+/** @import { InferredMorphism, Morphism } from './types.js' */
 
 const Nil = Symbol('Nil')
 
@@ -26,6 +26,27 @@ class ListPure extends AlgebraWithBase(Pure)(Category, Foldable, Monoid) {
     return Empty
   }
 
+  /**
+   * @template U
+   * @this {ListPure<T>}
+   * @param {Morphism<T, ListPure<U>>} f 
+   * @returns {ListPure<U>}
+   */
+  chain(f) {
+    return f(this.head())
+  }
+
+  /**
+   * @template U
+   * @this {ListPure<T>}
+   * @param {Morphism<T, U>} f 
+   * @returns {ListPure<U>}
+   */
+  map(f) {
+    return new ListPure(f(this._value))
+  }
+
+
   /**
    * @template U
    * @param {(acc: U, value: T) => U} f