diff --git a/seed/php-sdk/unions/src/Union/Types/Shape.php b/seed/php-sdk/unions/src/Union/Types/Shape.php
new file mode 100644
index 00000000000..51d28e82051
--- /dev/null
+++ b/seed/php-sdk/unions/src/Union/Types/Shape.php
@@ -0,0 +1,104 @@
+<?php
+
+class Circle {}
+
+class Square {}
+
+interface ShapeVisitor
+{
+    public function visitCircle(Circle $circle);
+    public function visitSquare(Square $square);
+    public function _visitUnknown(object $unknown);
+}
+
+enum ShapeType
+{
+    case CIRCLE;
+    case SQUARE;
+    case UNKNOWN;
+}
+
+readonly class Shape
+{
+    /**
+     * @var ShapeType $type
+     */
+    public ShapeType $type;
+
+    /**
+     * @var ?Circle $circle
+     */
+    private ?Circle $circle;
+
+    /**
+     * @var ?Square $square
+     */
+    private ?Square $square;
+
+    /**
+     * @var ?object $unknown
+     */
+    private ?object $unknown;
+
+    /**
+     * @param ?array{
+     *   type?: ShapeType,
+     *   circle?: ?Circle,
+     *   square?: ?Square,
+     *   unknown?: ?object,
+     * } $options
+     */
+    private function __construct(
+        private readonly ?array $options = null,
+    ) {
+        $this->type = $this->options['type'] ?? ShapeType::UNKNOWN;
+        $this->circle = $this->options['circle'] ?? null;
+        $this->square = $this->options['square'] ?? null;
+        $this->unknown = $this->options['unknown'] ?? null;
+    }
+
+    /**
+     * @param 
+     */
+    static function circle(Circle $circle): Shape
+    {
+        return new Shape([
+            'type' => ShapeType::CIRCLE,
+            'circle' => $circle
+        ]);
+    }
+
+    static function square(Square $square): Shape
+    {
+        return new Shape([
+            'type' => ShapeType::SQUARE,
+            'square' => $square
+        ]);
+    }
+
+    static function _unknown(object $unknown): Shape
+    {
+        return new Shape([
+            'unknown' => $unknown
+        ]);
+    }
+
+    public function isCircle(): bool
+    {
+        return $this->type == ShapeType::CIRCLE;
+    }
+
+    public function isSquare(): bool
+    {
+        return $this->type == ShapeType::SQUARE;
+    }
+
+    public function visit(ShapeVisitor $visitor)
+    {
+        return match ($this->type) {
+            ShapeType::CIRCLE => $visitor->visitCircle($this->circle),
+            ShapeType::SQUARE => $visitor->visitSquare($this->square),
+            ShapeType::UNKNOWN => $visitor->_visitUnknown($this),
+        };
+    }
+}