diff --git a/patterns/gmf.hexpat b/patterns/gmf.hexpat
new file mode 100644
index 0000000..13f4f43
--- /dev/null
+++ b/patterns/gmf.hexpat
@@ -0,0 +1,229 @@
+#pragma author DmitriLeon2000
+#pragma description Game Maker 3.x data
+#pragma endian little
+
+import std.mem;
+import std.io;
+
+struct Colors {
+    u8 red   [[color("FF0000")]];
+    u8 green [[color("00FF00")]];
+    u8 blue  [[color("0000FF")]];
+    padding[1];
+} [[static, color(std::format("{:02X}{:02X}{:02X}", red, green, blue)),
+    hex::inline_visualize("color", red, green, blue, 255)]];
+
+struct PascalString {
+    u32 length;
+    char data[length];
+};
+
+struct BitmapData {
+    u8 type[2];
+    u32 size;
+    u8 data[size-6] [[sealed]];
+};
+
+enum BackgroundType : s32 {
+    Solid = 0,
+    Image = 1,
+    Gradient = 2,
+    None = 3
+};
+
+enum BackImageStyle : s32 {
+    Tile = 0,
+    Stretch = 1,
+    Scrolling = 2,
+    LeftTop = 3
+};
+
+enum Transition : u32 {
+    None = 0,
+    CreateFromLeft = 1,
+    CreateFromRight = 2,
+    CreateFromTop = 3,
+    CreateFromBottom = 4,
+    CreateFromCenter = 5,
+    ShiftFromLeft = 6,
+    ShiftFromRight = 7,
+    ShiftFromTop = 8,
+    ShiftFromBottom = 9,
+    PushFromLeft = 10,
+    PushFromRight = 11,
+    PushFromTop = 12,
+    PushFromBottom = 13
+};
+
+struct SpriteBoundingBox {
+    u32 left, right, bottom, top;
+};
+
+enum ActionID : s32 {
+    EnumerateActions = 0,
+    EndAction = 1,
+    MoveFixed = 101,
+    ReverseHorizontal = 102,
+    ReverseVertical = 103,
+    JumpPosition = 104,
+    JumpRandom = 105,
+    Bounce = 106,
+    SetSpeedHorizontal = 111,
+    SetSpeedVertical = 112,
+    SetGravity = 121,
+    SetFriction = 122,
+    MoveFree = 131,
+    SetAlarm = 201,
+    InstanceCreate = 311,
+    InstanceDestroy = 312,
+    InstanceChange = 313,
+    PositionDestroy = 321,
+    Sound = 401,
+    ShowMessage = 411,
+    SetScore = 421,
+    DisplayHighscore = 431,
+    GoToRoom = 501,
+    EndGame = 511,
+    Sleep = 521,
+    ExitEvent = 601,
+    CheckPlaceFree = 701,
+    CheckInstanceNumber = 702,
+    CheckPlaceObject = 703,
+    CheckPlaceCollision = 704,
+    CheckQuestion = 721,
+    Else = 751,
+    CheckExpression = 801,
+    ExecuteCode = 811,
+    SetVariable = 821,
+    BlockStart = 901,
+    BlockEnd = 902,
+    DrawImage = 1001,
+    DrawText = 1002,
+    SetFont = 1003
+};
+
+struct GameObjectAction {
+    s32 version_verify [[hidden]];
+    ActionID action_id;
+    s32 apply_to; // -1 - self; -2 - not available
+    bool relative;
+    padding[3];
+    u32 param_count;
+    PascalString params[param_count];
+    s32 action_group;
+};
+
+struct GameObjectSubEvent {
+    s32 subevent_number;
+    s32 version_verify [[hidden]];
+    u32 action_count;
+    GameObjectAction actions[action_count];
+};
+
+struct GameObjectEvent {
+    GameObjectSubEvent subevents[while(std::mem::read_unsigned($, 4) != 0xFFFFFFFF)];
+    padding[4];
+};
+
+struct GameSprite {
+    s32 version_verify [[hidden]];
+    s32 width, height;
+    SpriteBoundingBox bounding_box1;
+    u32 image_count;
+    BitmapData images[image_count];
+    SpriteBoundingBox bounding_box2;
+};
+
+struct GameObject {
+    s32 version_verify [[hidden]];
+    PascalString name;
+    bool solid;
+    padding[3];
+    bool active;
+    padding[3];
+    if (version_verify >= 320)
+        u32 parent_id;
+    GameObjectEvent events[13];
+    // Events: 0 - Create, 1 - Destroy, 2 - Alarm, 3 - Step, 4 - Collision,
+    // 5 - Meeting, 6 - Mouse, 7 - Keyboard, 8 - Other, 9 - Drawing
+    // 10 - Create duplicate, 11-13 - unused
+    s32 cap [[hidden]];
+    GameSprite sprite;
+} [[name(name.data)]];
+
+struct GameRoomView {
+    bool enabled;
+    padding[3];
+    if (parent.version_verify >= 320)
+        s32 left, top, left_cell, top_cell;
+    u32 width;
+    u32 height;
+    if (parent.version_verify >= 320) {
+        u32 border_horiz, border_vert;
+    } else
+        u32 border;
+    u32 object_to_follow;
+};
+
+struct GameRoomInstance {
+    s32 left, top, object_index;
+};
+
+struct GameRoom {
+    u32 version_verify [[hidden]];
+    PascalString name;
+    Colors back_color1;
+    if (version_verify >= 320) {
+        Colors back_color2;
+        bool vertical_gradient;
+        padding[3];
+    }
+    // specify the name of the external image file from the data folder
+    PascalString back_image_name;
+    BackgroundType back_type;
+    BackImageStyle back_image_style;
+    s32 back_scroll_speed_horizontal, back_scroll_speed_vertical;
+    s32 speed, width, height, cell_size;
+    if (version_verify >= 320) {
+        bool enable_views;
+        padding[3];
+        GameRoomView views[4];
+    } else
+        GameRoomView view;
+    if (version_verify >= 320) {
+        Transition transition;
+        u32 transition_time, transition_steps;
+    }
+    u32 instance_count;
+    GameRoomInstance instances[instance_count];
+} [[name(name.data)]];
+
+struct GameSound {
+    u32 version_verify [[hidden]];
+    PascalString name;
+    u32 reserved;
+    // specify the name of the external audio file from the data folder
+    PascalString filename;
+    bool allow_for_sound_effects;
+    padding[3];
+    u32 buffer_count;
+} [[name(name.data)]];
+
+struct GMF {
+    u32 version;
+    u32 verification[2];
+    u32 version_verify_options [[hidden]];
+    u32 option_count;
+    PascalString options[option_count];
+    u32 version_verify_objects [[hidden]];
+    u32 object_count;
+    GameObject objects[object_count];
+    u32 version_verify_rooms [[hidden]];
+    u32 room_count;
+    GameRoom rooms[room_count];
+    u32 version_verify_sounds [[hidden]];
+    u32 sound_count;
+    GameSound sounds[sound_count];
+};
+
+GMF gmf @ 0x0;
diff --git a/tests/patterns/test_data/gmf.hexpat/gmf.hexpat.gmf b/tests/patterns/test_data/gmf.hexpat/gmf.hexpat.gmf
new file mode 100644
index 0000000..ddb8bd6
Binary files /dev/null and b/tests/patterns/test_data/gmf.hexpat/gmf.hexpat.gmf differ
diff --git a/tests/patterns/test_data/gmf.hexpat/gmf.hexpat_data/help b/tests/patterns/test_data/gmf.hexpat/gmf.hexpat_data/help
new file mode 100644
index 0000000..5fba4b3
Binary files /dev/null and b/tests/patterns/test_data/gmf.hexpat/gmf.hexpat_data/help differ