diff --git a/user/src/bin/embed_graph.rs b/user/src/bin/embed_graph.rs
index 3866994cd414703a3d51dbae0674660bfd0c1ac3..e1b3ea8349366f153d943679fd14df057b23c2ba 100644
--- a/user/src/bin/embed_graph.rs
+++ b/user/src/bin/embed_graph.rs
@@ -1,13 +1,12 @@
 #![no_std]
 #![no_main]
 
-use user_lib::{framebuffer, framebuffer_flush};
-
 #[macro_use]
 extern crate user_lib;
-
 extern crate alloc;
 
+use user_lib::{framebuffer, framebuffer_flush};
+
 use embedded_graphics::pixelcolor::Rgb888;
 use embedded_graphics::prelude::{Drawable, Point, RgbColor, Size};
 use embedded_graphics::primitives::Primitive;
diff --git a/user/src/bin/embed_graph_uart.rs b/user/src/bin/embed_graph_uart.rs
new file mode 100644
index 0000000000000000000000000000000000000000..9e0933b064503a565f2896551ceb30193344ae18
--- /dev/null
+++ b/user/src/bin/embed_graph_uart.rs
@@ -0,0 +1,124 @@
+#![no_std]
+#![no_main]
+
+#[macro_use]
+extern crate user_lib;
+extern crate alloc;
+
+use user_lib::console::getchar;
+use user_lib::{framebuffer, framebuffer_flush};
+
+use embedded_graphics::pixelcolor::Rgb888;
+use embedded_graphics::prelude::{Drawable, Point, RgbColor, Size};
+use embedded_graphics::primitives::Primitive;
+use embedded_graphics::primitives::{PrimitiveStyle, Rectangle};
+use embedded_graphics::{draw_target::DrawTarget, prelude::OriginDimensions};
+
+pub const VIRTGPU_XRES: usize = 1280;
+pub const VIRTGPU_YRES: usize = 800;
+pub const VIRTGPU_LEN: usize = VIRTGPU_XRES * VIRTGPU_YRES * 4;
+
+const INIT_X: i32 = 640;
+const INIT_Y: i32 = 400;
+const RECT_SIZE: u32 = 40;
+
+pub struct Display {
+    pub size: Size,
+    pub point: Point,
+    //pub fb: Arc<&'static mut [u8]>,
+    pub fb: &'static mut [u8],
+}
+
+impl Display {
+    pub fn new(size: Size, point: Point) -> Self {
+        let fb_ptr = framebuffer() as *mut u8;
+        println!(
+            "Hello world from user mode program! 0x{:X} , len {}",
+            fb_ptr as usize, VIRTGPU_LEN
+        );
+        let fb =
+            unsafe { core::slice::from_raw_parts_mut(fb_ptr as *mut u8, VIRTGPU_LEN as usize) };
+        Self { size, point, fb }
+    }
+}
+
+impl OriginDimensions for Display {
+    fn size(&self) -> Size {
+        self.size
+    }
+}
+
+impl DrawTarget for Display {
+    type Color = Rgb888;
+
+    type Error = core::convert::Infallible;
+
+    fn draw_iter<I>(&mut self, pixels: I) -> Result<(), Self::Error>
+    where
+        I: IntoIterator<Item = embedded_graphics::Pixel<Self::Color>>,
+    {
+        pixels.into_iter().for_each(|px| {
+            let idx = ((self.point.y + px.0.y) * VIRTGPU_XRES as i32 + self.point.x + px.0.x)
+                as usize
+                * 4;
+            if idx + 2 >= self.fb.len() {
+                return;
+            }
+            self.fb[idx] = px.1.b();
+            self.fb[idx + 1] = px.1.g();
+            self.fb[idx + 2] = px.1.r();
+        });
+        framebuffer_flush();
+        Ok(())
+    }
+}
+
+pub struct DrawingBoard {
+    disp: Display,
+    latest_pos: Point,
+}
+
+impl DrawingBoard {
+    pub fn new() -> Self {
+        Self {
+            disp: Display::new(Size::new(1280, 800), Point::new(0, 0)),
+            latest_pos: Point::new(INIT_X, INIT_Y),
+        }
+    }
+    fn paint(&mut self) {
+        Rectangle::with_center(self.latest_pos, Size::new(RECT_SIZE, RECT_SIZE))
+            .into_styled(PrimitiveStyle::with_stroke(Rgb888::WHITE, 1))
+            .draw(&mut self.disp)
+            .ok();
+    }
+    fn unpaint(&mut self) {
+        Rectangle::with_center(self.latest_pos, Size::new(RECT_SIZE, RECT_SIZE))
+            .into_styled(PrimitiveStyle::with_stroke(Rgb888::BLACK, 1))
+            .draw(&mut self.disp)
+            .ok();
+    }
+    pub fn move_rect(&mut self, dx: i32, dy: i32) {
+        self.unpaint();
+        self.latest_pos.x += dx;
+        self.latest_pos.y += dy;
+        self.paint();
+    }
+}
+
+const LF: u8 = 0x0au8;
+const CR: u8 = 0x0du8;
+#[no_mangle]
+pub fn main() -> i32 {
+    // let fb_ptr = framebuffer() as *mut u8;
+    let mut board = DrawingBoard::new();
+    for i in 0..20 {
+        let c=getchar();
+        if c == LF || c == CR {
+            break;
+        }
+        board.latest_pos.x += i;
+        board.latest_pos.y += i;
+        board.paint();
+    }
+    0
+}
diff --git a/user/src/bin/gui_simple.rs b/user/src/bin/gui_simple.rs
index df4cfbb871771486de7f49d677f72c0520d284ed..83fb721d7843c087913a3bb430ad4b48d822736e 100644
--- a/user/src/bin/gui_simple.rs
+++ b/user/src/bin/gui_simple.rs
@@ -1,19 +1,11 @@
 #![no_std]
 #![no_main]
 
-use user_lib::{framebuffer, framebuffer_flush};
-
 #[macro_use]
 extern crate user_lib;
 
-// use embedded_graphics::pixelcolor::Rgb888;
-// use embedded_graphics::prelude::{Drawable, Point, RgbColor, Size};
-// use embedded_graphics::primitives::Primitive;
-// use embedded_graphics::primitives::{PrimitiveStyle, Rectangle};
-// use embedded_graphics::{
-//     draw_target::DrawTarget,
-//     prelude::{OriginDimensions},
-// };
+use user_lib::{framebuffer, framebuffer_flush};
+
 pub const VIRTGPU_XRES: usize = 1280;
 pub const VIRTGPU_YRES: usize = 800;