diff --git a/lib_sharp.c b/lib_sharp.c
index 85dc7de..584d49c 100644
--- a/lib_sharp.c
+++ b/lib_sharp.c
@@ -17,6 +17,18 @@ uint8_t mirror_bytes(uint8_t byte)
     return res;
 }
 
+void swap_uint16(uint16_t *a, uint16_t *b)
+{
+    uint16_t t = *a;
+    *a = *b;
+    *b = t;
+}
+
+uint16_t min_uint16(uint16_t a, uint16_t b)
+{
+    return a < b ? a : b;
+}
+
 sharp_display_t sharp_display_new(uint16_t width, uint16_t height, spi_inst_t * spi, uint8_t cs)
 {
     gpio_put(cs, false);
@@ -42,7 +54,7 @@ void sharp_display_refresh_screen(sharp_display_t * display)
 {
     uint8_t spi_byte;
 
-    gpio_put(display->cs, 1);
+    gpio_put(display->cs, true);
     sharp_display_toggle_vcom(display);
 
     uint16_t line_size = display->width / 8;
@@ -72,12 +84,12 @@ void sharp_display_refresh_screen(sharp_display_t * display)
     spi_byte = 0b00000000;
     spi_write_blocking(display->spi, &spi_byte, 1);
 
-    gpio_put(display->cs, 0);
+    gpio_put(display->cs, false);
 }
 
 void sharp_display_clear_screen(sharp_display_t * display)
 {
-    gpio_put(display->cs, 1);
+    gpio_put(display->cs, true);
     sharp_display_toggle_vcom(display);
 
     memset(display->framebuffer, 0b00000000, (display->width * display->height) / 8);
@@ -87,7 +99,7 @@ void sharp_display_clear_screen(sharp_display_t * display)
     buff[1] = 0b00000000;
 
     spi_write_blocking(display->spi, buff, 2);
-    gpio_put(display->cs, 0);
+    gpio_put(display->cs, false);
 }
 
 void sharp_display_toggle_vcom(sharp_display_t * display)
@@ -95,26 +107,80 @@ void sharp_display_toggle_vcom(sharp_display_t * display)
     display->vcom ^= CMD_VCOM;
 }
 
-void sharp_display_draw_pixel(sharp_display_t *display, uint16_t x, uint16_t y, sharp_color_t color)
+void sharp_display_set_buffer(sharp_display_t * display, sharp_color_t color)
 {
-    if (x < 0 || x >= display->width || y < 0 || y >= display->height) return;
-
-    uint16_t pixel_in_byte = x % 8;
-    uint16_t column_in_bytes = (x - pixel_in_byte) / 8;
-    uint8_t mask = 0b000000001 << pixel_in_byte;
-
-    if (color == WHITE) {
-        display->framebuffer[y*(display->width / 8) + column_in_bytes] |= ~mask;
-    } else {
-        display->framebuffer[y*(display->width / 8) + column_in_bytes] &= ~mask;
-    }
-}
-
-void sharp_display_fill_screen(sharp_display_t * display, sharp_color_t color)
-{
-    if (color == WHITE) {
+    switch (color) {
+    case WHITE:
         memset(display->framebuffer, 0b11111111, (display->width * display->height) / 8);
-    } else {
+        break;
+    case LIGHT_GRAY:
+    case DARK_GRAY:
+        for (size_t x = 0; x < display->width; x += 1)
+        {
+            for (size_t y = 0; y < display->height; y += 1)
+            {
+                sharp_display_draw_pixel(display, x, y, color);
+            }
+        }
+        break;
+    case BLACK:
         memset(display->framebuffer, 0b00000000, (display->width * display->height) / 8);
+        break;
+    }
+}
+
+void sharp_display_draw_pixel(sharp_display_t * display, uint16_t x, uint16_t y, sharp_color_t color)
+{
+    if (x < 0 || x >= display->width || y < 0 || y >= display->height)
+    {
+        return;
+    }
+
+    uint8_t byte = x % 8;
+    uint16_t row = y * (display->width / 8);
+    uint16_t col = (x - byte) / 8;
+    uint8_t mask = 0b000000001 << byte;
+
+    switch (color) {
+    case WHITE:
+        display->framebuffer[row + col] |= ~mask;
+        break;
+    case LIGHT_GRAY:
+        if (x % 3 || y % 3)
+        {
+            display->framebuffer[row + col] |= mask;
+        }
+        else
+        {
+            display->framebuffer[row + col] &= ~mask;
+        }
+        break;
+    case DARK_GRAY:
+        if (x % 2)
+        {
+            display->framebuffer[row + col] |= mask;
+        }
+        else
+        {
+            display->framebuffer[row + col] &= ~mask;
+        }
+        break;
+    case BLACK:
+        display->framebuffer[row + col] &= ~mask;
+        break;
+    }
+}
+
+void sharp_display_draw_filled_rectangle(sharp_display_t * display, uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint16_t color)
+{
+    w = min_uint16(w, display->width);
+    h = min_uint16(h, display->height);
+
+    for (uint16_t i = 0; i < h; i += 1)
+    {
+        for (uint16_t j = 0; j < w; j += 1)
+        {
+            sharp_display_draw_pixel(display, x + j, y + i, color);
+        }
     }
 }
diff --git a/lib_sharp.h b/lib_sharp.h
index e01d5f6..b34a327 100644
--- a/lib_sharp.h
+++ b/lib_sharp.h
@@ -10,8 +10,10 @@
 
 typedef enum sharp_color
 {
-    WHITE = 0,
-    BLACK = 1,
+    WHITE,
+    LIGHT_GRAY,
+    DARK_GRAY,
+    BLACK,
 }
 sharp_color_t;
 
@@ -27,10 +29,14 @@ sharp_display_t;
 
 sharp_display_t sharp_display_new(uint16_t width, uint16_t height, spi_inst_t * spi, uint8_t cs);
 bool sharp_display_error(sharp_display_t * display);
+
 void sharp_display_refresh_screen(sharp_display_t * display);
 void sharp_display_clear_screen(sharp_display_t * display);
 void sharp_display_toggle_vcom(sharp_display_t * display);
-void sharp_display_draw_pixel(sharp_display_t *display, uint16_t x, uint16_t y, sharp_color_t color);
-void sharp_display_fill_screen(sharp_display_t * display, sharp_color_t color);
+
+void sharp_display_set_buffer(sharp_display_t * display, sharp_color_t color);
+
+void sharp_display_draw_pixel(sharp_display_t * display, uint16_t x, uint16_t y, sharp_color_t color);
+void sharp_display_draw_filled_rectangle(sharp_display_t * display, uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint16_t color);
 
 #endif