diff --git a/java/dev/enola/thing/PredicatesObjects.java b/java/dev/enola/thing/PredicatesObjects.java
index 7f70da3c..827ec511 100644
--- a/java/dev/enola/thing/PredicatesObjects.java
+++ b/java/dev/enola/thing/PredicatesObjects.java
@@ -65,6 +65,11 @@ default boolean isIterable(String predicateIRI) {
         return value instanceof Iterable;
     }
 
+    default boolean isOrdered(String predicateIRI) {
+        var value = get(predicateIRI);
+        return value instanceof List;
+    }
+
     default boolean isStruct(String predicateIRI) {
         var value = get(predicateIRI);
         return value instanceof PredicatesObjects;
@@ -182,4 +187,36 @@ interface Builder<B extends PredicatesObjects> // skipcq: JAVA-E0169
         @Override
         B build();
     }
+
+    // TODO How to best name this, and the equivalent in Thing?
+    interface Builder2<B extends PredicatesObjects> extends PredicatesObjects.Builder<B> {
+
+        /**
+         * Adds one of possibly several value objects for the given predicate IRI.
+         *
+         * <p>This is UNORDERED! Insertion order may NOT be preserved. Duplicates are not allowed
+         * and cause an error. It is an error if this property has already been set to anything else
+         * than a {@link Set}.
+         */
+        <@ImmutableTypeParameter T> PredicatesObjects.Builder2<B> add(String predicateIRI, T value);
+
+        <@ImmutableTypeParameter T> PredicatesObjects.Builder2<B> add(
+                String predicateIRI, T value, @Nullable String datatypeIRI);
+
+        /**
+         * Adds one of possibly several value objects for the given predicate IRI - and preserves
+         * order.
+         *
+         * <p>Duplicates ARE allowed. It is an error if this property has already been set to
+         * anything else than a {@link List}.
+         */
+        <@ImmutableTypeParameter T> PredicatesObjects.Builder2<B> addOrdered(
+                String predicateIRI, T value);
+
+        <@ImmutableTypeParameter T> PredicatesObjects.Builder2<B> addOrdered(
+                String predicateIRI, T value, @Nullable String datatypeIRI);
+
+        @Override
+        B build();
+    }
 }
diff --git a/java/dev/enola/thing/Thing.java b/java/dev/enola/thing/Thing.java
index ead6d9be..4b67b138 100644
--- a/java/dev/enola/thing/Thing.java
+++ b/java/dev/enola/thing/Thing.java
@@ -17,8 +17,12 @@
  */
 package dev.enola.thing;
 
+import com.google.errorprone.annotations.ImmutableTypeParameter;
+
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * Thing is the central data structure of Enola.
  *
@@ -45,9 +49,24 @@ interface Builder<B extends Thing> extends PredicatesObjects.Builder<B> { // ski
 
         Builder<B> set(String predicateIRI, Object value);
 
-        Builder<B> set(String predicateIRI, Object value, String datatypeIRI);
+        Builder<B> set(String predicateIRI, Object value, @Nullable String datatypeIRI);
 
         @Override
         B build();
     }
+
+    // TODO How to best name this, and the equivalent in PredicatesObjects?
+    @SuppressFBWarnings("NM_SAME_SIMPLE_NAME_AS_INTERFACE")
+    interface Builder2<B extends Thing> extends Thing.Builder<B>, PredicatesObjects.Builder2<B> {
+
+        <@ImmutableTypeParameter T> Thing.Builder2<B> add(String predicateIRI, T value);
+
+        <@ImmutableTypeParameter T> Thing.Builder2<B> add(
+                String predicateIRI, T value, @Nullable String datatypeIRI);
+
+        <@ImmutableTypeParameter T> Thing.Builder2<B> addOrdered(String predicateIRI, T value);
+
+        <@ImmutableTypeParameter T> Thing.Builder2<B> addOrdered(
+                String predicateIRI, T value, @Nullable String datatypeIRI);
+    }
 }