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diff --git a/dynamiccolor/ToneDeltaPair.java b/dynamiccolor/ToneDeltaPair.java
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+/*
+ * Copyright 2023 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.ux.material.libmonet.dynamiccolor;
+
+import androidx.annotation.NonNull;
+
+/**
+ * Documents a constraint between two DynamicColors, in which their tones must have a certain
+ * distance from each other.
+ *
+ * <p>Prefer a DynamicColor with a background, this is for special cases when designers want tonal
+ * distance, literally contrast, between two colors that don't have a background / foreground
+ * relationship or a contrast guarantee.
+ */
+public final class ToneDeltaPair {
+  /** The first role in a pair. */
+  private final DynamicColor roleA;
+
+  /** The second role in a pair. */
+  private final DynamicColor roleB;
+
+  /** Required difference between tones. Absolute value, negative values have undefined behavior. */
+  private final double delta;
+
+  /** The relative relation between tones of roleA and roleB, as described above. */
+  private final TonePolarity polarity;
+
+  /**
+   * Whether these two roles should stay on the same side of the "awkward zone" (T50-59). This is
+   * necessary for certain cases where one role has two backgrounds.
+   */
+  private final boolean stayTogether;
+
+  /**
+   * Documents a constraint in tone distance between two DynamicColors.
+   *
+   * <p>The polarity is an adjective that describes "A", compared to "B".
+   *
+   * <p>For instance, ToneDeltaPair(A, B, 15, 'darker', stayTogether) states that A's tone should be
+   * at least 15 darker than B's.
+   *
+   * <p>'nearer' and 'farther' describes closeness to the surface roles. For instance,
+   * ToneDeltaPair(A, B, 10, 'nearer', stayTogether) states that A should be 10 lighter than B in
+   * light mode, and 10 darker than B in dark mode.
+   *
+   * @param roleA The first role in a pair.
+   * @param roleB The second role in a pair.
+   * @param delta Required difference between tones. Absolute value, negative values have undefined
+   *     behavior.
+   * @param polarity The relative relation between tones of roleA and roleB, as described above.
+   * @param stayTogether Whether these two roles should stay on the same side of the "awkward zone"
+   *     (T50-59). This is necessary for certain cases where one role has two backgrounds.
+   */
+  public ToneDeltaPair(
+      DynamicColor roleA,
+      DynamicColor roleB,
+      double delta,
+      TonePolarity polarity,
+      boolean stayTogether) {
+    this.roleA = roleA;
+    this.roleB = roleB;
+    this.delta = delta;
+    this.polarity = polarity;
+    this.stayTogether = stayTogether;
+  }
+
+  @NonNull
+  public DynamicColor getRoleA() {
+    return roleA;
+  }
+
+  @NonNull
+  public DynamicColor getRoleB() {
+    return roleB;
+  }
+
+  @NonNull
+  public double getDelta() {
+    return delta;
+  }
+
+  @NonNull
+  public TonePolarity getPolarity() {
+    return polarity;
+  }
+
+  @NonNull
+  public boolean getStayTogether() {
+    return stayTogether;
+  }
+}