activity_home.xml

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/constraint_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#263238">

    <View
        android:id="@+id/space_background"
        android:layout_width="140dp"
        android:layout_height="140dp"
        android:background="@drawable/bg"
        app:layout_constraintBottom_toTopOf="@+id/ai_background"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toLeftOf="@+id/science_background"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_chainStyle="packed" />

    <View
        android:id="@+id/science_background"
        android:layout_width="140dp"
        android:layout_height="140dp"
        android:layout_marginStart="32dp"
        android:background="@drawable/bg"
        app:layout_constraintLeft_toRightOf="@id/space_background"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="@+id/space_background" />

    <View
        android:id="@+id/ai_background"
        android:layout_width="140dp"
        android:layout_height="140dp"
        android:layout_marginTop="32dp"
        android:background="@drawable/bg"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="@id/space_background"
        app:layout_constraintTop_toBottomOf="@+id/space_background" />

    <View
        android:id="@+id/nature_background"
        android:layout_width="140dp"
        android:layout_height="140dp"
        android:background="@drawable/bg"
        app:layout_constraintBottom_toBottomOf="@+id/ai_background"
        app:layout_constraintLeft_toLeftOf="@+id/science_background"
        app:layout_constraintRight_toRightOf="@+id/science_background"
        app:layout_constraintTop_toTopOf="@+id/ai_background" />

    <View
        android:id="@+id/selector"
        android:layout_width="140dp"
        android:layout_height="140dp"
        android:background="@drawable/selector_bg"
        app:layout_constraintBottom_toBottomOf="@+id/space_background"
        app:layout_constraintLeft_toLeftOf="@+id/space_background"
        app:layout_constraintRight_toRightOf="@+id/space_background"
        app:layout_constraintTop_toTopOf="@+id/space_background" />

    <ImageView
        android:id="@+id/space"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:scaleType="centerInside"
        android:src="@drawable/planet"
        android:tint="@android:color/white"
        app:layout_constraintBottom_toBottomOf="@+id/space_background"
        app:layout_constraintLeft_toLeftOf="@+id/space_background"
        app:layout_constraintRight_toRightOf="@+id/space_background"
        app:layout_constraintTop_toTopOf="@+id/space_background" />

    <ImageView
        android:id="@+id/science"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:scaleType="centerInside"
        android:src="@drawable/atom"
        android:tint="@android:color/white"
        app:layout_constraintBottom_toBottomOf="@+id/science_background"
        app:layout_constraintLeft_toLeftOf="@+id/science_background"
        app:layout_constraintRight_toRightOf="@+id/science_background"
        app:layout_constraintTop_toTopOf="@+id/science_background" />

    <ImageView
        android:id="@+id/nature"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:scaleType="centerInside"
        android:src="@drawable/earth"
        android:tint="@android:color/white"
        app:layout_constraintBottom_toBottomOf="@+id/nature_background"
        app:layout_constraintLeft_toLeftOf="@+id/nature_background"
        app:layout_constraintRight_toRightOf="@+id/nature_background"
        app:layout_constraintTop_toTopOf="@+id/nature_background" />

    <ImageView
        android:id="@+id/ai"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:scaleType="centerInside"
        android:src="@drawable/brain"
        android:tint="@android:color/white"
        app:layout_constraintBottom_toBottomOf="@+id/ai_background"
        app:layout_constraintLeft_toLeftOf="@+id/ai_background"
        app:layout_constraintRight_toRightOf="@+id/ai_background"
        app:layout_constraintTop_toTopOf="@+id/ai_background" />

</android.support.constraint.ConstraintLayout>