diff --git a/src/display.rs b/src/display.rs
index 51f543c..50e2d1a 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -1,3 +1,5 @@
+use core::ops::Mul;
+
 use atmega_hal::{
     Spi,
     port::{self, Pin, PinOps, mode},
@@ -5,6 +7,7 @@ use atmega_hal::{
 };
 use embedded_hal::{delay::DelayNs, digital::OutputPin, spi::SpiBus};
 
+#[derive(Clone, Copy)]
 pub struct Rgb565(pub u8, pub u8, pub u8);
 
 impl Rgb565 {
@@ -15,6 +18,42 @@ impl Rgb565 {
 
         Color::from(r | b | g)
     }
+
+    pub fn red() -> Rgb565 {
+        Rgb565(255, 0, 0)
+    }
+
+    pub fn green() -> Rgb565 {
+        Rgb565(0, 255, 0)
+    }
+
+    pub fn blue() -> Rgb565 {
+        Rgb565(0, 0, 255)
+    }
+
+    pub fn yellow() -> Rgb565 {
+        Rgb565(255, 255, 0)
+    }
+
+    pub fn purple() -> Rgb565 {
+        Rgb565(255, 0, 255)
+    }
+
+    pub fn cyan() -> Rgb565 {
+        Rgb565(0, 255, 255)
+    }
+}
+
+impl Mul<f32> for Rgb565 {
+    type Output = Rgb565;
+
+    fn mul(self, rhs: f32) -> Self::Output {
+        Rgb565(
+            (self.0 as f32 * rhs) as u8,
+            (self.1 as f32 * rhs) as u8,
+            (self.2 as f32 * rhs) as u8,
+        )
+    }
 }
 
 #[derive(Default, Clone, Copy)]
diff --git a/src/font.rs b/src/font.rs
new file mode 100644
index 0000000..13f7837
--- /dev/null
+++ b/src/font.rs
@@ -0,0 +1,9 @@
+fn letter(character: char) -> [u8; 8] {
+    match character {
+        'a' => [
+            0b01111110, 0b01000010, 0b10000001, 0b11111111, 0b10000001, 0b10000001, 0b10000001,
+            0b10000001,
+        ],
+        _ => [0; 8],
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 437b5cf..0cbc359 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,7 +5,7 @@
 #![no_main]
 
 use atmega_hal::{
-    Usart,
+    Adc, Usart,
     spi::{self, Settings},
     usart::Baudrate,
 };
@@ -15,6 +15,7 @@ use panic_halt as _;
 use crate::display::{Display, Position, Rgb565};
 
 mod display;
+mod font;
 mod image;
 
 type CoreClock = atmega_hal::clock::MHz8;
@@ -61,17 +62,27 @@ fn main() -> ! {
 
     display.init();
 
+    let mut adc: Adc<CoreClock> = atmega_hal::Adc::new(dp.ADC, Default::default());
+
+    let button = pins.pd5.into_pull_up_input();
+    let potentiometer = pins.pc1.into_analog_input(&mut adc);
+
+    let colors = [Rgb565::red(), Rgb565::green(), Rgb565::blue()];
+    let mut idx = 0;
+
     let mut delay = atmega_hal::delay::Delay::<CoreClock>::new();
-    let mut color = 0;
     loop {
-        // color += 40;
-        delay.delay_ms(1000);
+        let raw_input = potentiometer.analog_read(&mut adc);
+        let input = raw_input as f32 / 1024f32;
+
         display.draw_rect(
             Position { x: 0, y: 0 },
             Position { x: 200, y: 200 },
-            Rgb565(color % 255, color % 100, color % 50).as_color(),
+            (colors[idx] * input).as_color(),
         );
-        color = color + 50;
-        ufmt::uwriteln!(&mut serial, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA").unwrap();
+        if button.is_low() {
+            idx = (idx + 1) % colors.len();
+        }
+        delay.delay_ms(1000);
     }
 }