diff --git a/eo-runtime/src/main/java/org/eolang/PhConst.java b/eo-runtime/src/main/java/org/eolang/PhConst.java
index 615a2c19be..7463a62d4d 100644
--- a/eo-runtime/src/main/java/org/eolang/PhConst.java
+++ b/eo-runtime/src/main/java/org/eolang/PhConst.java
@@ -35,12 +35,7 @@
  * @since 0.16
  */
 @Versionized
-public final class PhConst implements Phi {
-
-    /**
-     * The origin being turned into a const.
-     */
-    private final Phi origin;
+public final class PhConst extends PhDecorator {
 
     /**
      * Cached attributes.
@@ -53,7 +48,7 @@ public final class PhConst implements Phi {
      * @param phi The origin
      */
     public PhConst(final Phi phi) {
-        this.origin = phi;
+        super(phi);
     }
 
     @Override
diff --git a/eo-runtime/src/main/java/org/eolang/PhDecorator.java b/eo-runtime/src/main/java/org/eolang/PhDecorator.java
new file mode 100644
index 0000000000..5d2c093cc5
--- /dev/null
+++ b/eo-runtime/src/main/java/org/eolang/PhDecorator.java
@@ -0,0 +1,23 @@
+package org.eolang;
+
+public abstract class PhDecorator implements Phi{
+
+    /**
+     * The original.
+     */
+    protected final Phi origin;
+
+    PhDecorator(final Phi phi) {
+        this.origin = phi;
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        return this.origin.equals(obj);
+    }
+
+    @Override
+    public int hashCode() {
+        return this.origin.hashCode();
+    }
+}
diff --git a/eo-runtime/src/main/java/org/eolang/PhImmovable.java b/eo-runtime/src/main/java/org/eolang/PhImmovable.java
index eda2831af9..6ce8df8ac1 100644
--- a/eo-runtime/src/main/java/org/eolang/PhImmovable.java
+++ b/eo-runtime/src/main/java/org/eolang/PhImmovable.java
@@ -30,12 +30,7 @@
  * @since 0.23
  */
 @Versionized
-final class PhImmovable implements Phi {
-
-    /**
-     * The original.
-     */
-    private final Phi origin;
+final class PhImmovable extends PhDecorator {
 
     /**
      * Ctor.
@@ -43,17 +38,7 @@ final class PhImmovable implements Phi {
      * @param phi The object
      */
     PhImmovable(final Phi phi) {
-        this.origin = phi;
-    }
-
-    @Override
-    public boolean equals(final Object obj) {
-        return this.origin.equals(obj);
-    }
-
-    @Override
-    public int hashCode() {
-        return this.origin.hashCode();
+        super(phi);
     }
 
     @Override
diff --git a/eo-runtime/src/main/java/org/eolang/PhLocated.java b/eo-runtime/src/main/java/org/eolang/PhLocated.java
index 8532baed29..6bc53201f3 100644
--- a/eo-runtime/src/main/java/org/eolang/PhLocated.java
+++ b/eo-runtime/src/main/java/org/eolang/PhLocated.java
@@ -30,12 +30,7 @@
  * @since 0.21
  */
 @Versionized
-public final class PhLocated implements Phi {
-
-    /**
-     * The original.
-     */
-    private final Phi origin;
+public final class PhLocated extends PhDecorator {
 
     /**
      * The line number.
@@ -73,22 +68,12 @@ public PhLocated(final Phi phi, final int lne, final int pos) {
      * @checkstyle ParameterNumberCheck (5 lines)
      */
     public PhLocated(final Phi phi, final int lne, final int pos, final String loc) {
-        this.origin = phi;
+        super(phi);
         this.line = lne;
         this.position = pos;
         this.location = loc;
     }
 
-    @Override
-    public boolean equals(final Object obj) {
-        return this.origin.equals(obj);
-    }
-
-    @Override
-    public int hashCode() {
-        return this.origin.hashCode();
-    }
-
     @Override
     public String toString() {
         return String.format(
diff --git a/eo-runtime/src/main/java/org/eolang/PhLogged.java b/eo-runtime/src/main/java/org/eolang/PhLogged.java
index e0d2725904..ffdf6b15a7 100644
--- a/eo-runtime/src/main/java/org/eolang/PhLogged.java
+++ b/eo-runtime/src/main/java/org/eolang/PhLogged.java
@@ -33,12 +33,7 @@
  * @since 0.24
  */
 @Versionized
-public final class PhLogged implements Phi {
-
-    /**
-     * The origin being turned into a const.
-     */
-    private final Phi origin;
+public final class PhLogged extends PhDecorator {
 
     /**
      * Ctor.
@@ -46,7 +41,7 @@ public final class PhLogged implements Phi {
      * @param phi The origin
      */
     public PhLogged(final Phi phi) {
-        this.origin = phi;
+        super(phi);
     }
 
     @Override
diff --git a/eo-runtime/src/main/java/org/eolang/PhNamed.java b/eo-runtime/src/main/java/org/eolang/PhNamed.java
index ab292f634f..38fea6a743 100644
--- a/eo-runtime/src/main/java/org/eolang/PhNamed.java
+++ b/eo-runtime/src/main/java/org/eolang/PhNamed.java
@@ -30,12 +30,7 @@
  * @since 0.17
  */
 @Versionized
-final class PhNamed implements Phi {
-
-    /**
-     * The original.
-     */
-    private final Phi origin;
+final class PhNamed extends PhDecorator {
 
     /**
      * The name.
@@ -49,7 +44,7 @@ final class PhNamed implements Phi {
      * @param txt The name
      */
     PhNamed(final Phi phi, final String txt) {
-        this.origin = phi;
+        super(phi);
         this.name = txt;
     }
 
diff --git a/eo-runtime/src/main/java/org/eolang/PhSafe.java b/eo-runtime/src/main/java/org/eolang/PhSafe.java
index 2513de6be3..516da46e3a 100644
--- a/eo-runtime/src/main/java/org/eolang/PhSafe.java
+++ b/eo-runtime/src/main/java/org/eolang/PhSafe.java
@@ -33,29 +33,13 @@
  * @since 0.26
  */
 @Versionized
-public final class PhSafe implements Phi {
-
-    /**
-     * The original.
-     */
-    private final Phi origin;
-
+public final class PhSafe extends PhDecorator {
     /**
      * Ctor.
      * @param phi The object
      */
     public PhSafe(final Phi phi) {
-        this.origin = phi;
-    }
-
-    @Override
-    public boolean equals(final Object obj) {
-        return this.origin.equals(obj);
-    }
-
-    @Override
-    public int hashCode() {
-        return this.origin.hashCode();
+        super(phi);
     }
 
     @Override