diff --git a/src/main.rs b/src/main.rs
index bf3118e..787fb7a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -102,37 +102,17 @@ fn main() -> ! {
     log::info!("Sleeping for 0.5s...");
     // delay.delay(500.millis());
 
-    let mut gpio2 = Input::new(io.pins.gpio2, Pull::Up);
-    let mut gpio3 = Input::new(io.pins.gpio3, Pull::Up);
-    let mut gpio4 = Input::new(io.pins.gpio4, Pull::Up);
-    let mut gpio5 = Input::new(io.pins.gpio5, Pull::Up);
-
-    let mut gpio6 = OutputOpenDrain::new(io.pins.gpio6, Level::Low, Pull::Up);
-    let mut gpio7 = OutputOpenDrain::new(io.pins.gpio7, Level::Low, Pull::Up);
-    let mut gpio8 = OutputOpenDrain::new(io.pins.gpio8, Level::Low, Pull::Up);
-    let mut gpio10 = OutputOpenDrain::new(io.pins.gpio10, Level::Low, Pull::Up);
-
-    let mut kbd = Keypad((
-        (&mut gpio2, &mut gpio6),
-        (&mut gpio3, &mut gpio6),
-        (&mut gpio4, &mut gpio6),
-        (&mut gpio5, &mut gpio6),
-        // --------------------------------------
-        (&mut gpio2, &mut gpio7),
-        (&mut gpio3, &mut gpio7),
-        (&mut gpio4, &mut gpio7),
-        (&mut gpio5, &mut gpio7),
-        // --------------------------------------
-        (&mut gpio2, &mut gpio8),
-        (&mut gpio3, &mut gpio8),
-        (&mut gpio4, &mut gpio8),
-        (&mut gpio5, &mut gpio8),
-        // --------------------------------------
-        (&mut gpio2, &mut gpio10),
-        (&mut gpio3, &mut gpio10),
-        (&mut gpio4, &mut gpio10),
-        (&mut gpio5, &mut gpio10),
-    ));
+    let mut kbd = Keypad {
+        i1: Input::new(io.pins.gpio2, Pull::Up),
+        i2: Input::new(io.pins.gpio3, Pull::Up),
+        i3: Input::new(io.pins.gpio4, Pull::Up),
+        i4: Input::new(io.pins.gpio5, Pull::Up),
+        //---------------------------
+        o1: OutputOpenDrain::new(io.pins.gpio6, Level::Low, Pull::Up),
+        o2: OutputOpenDrain::new(io.pins.gpio7, Level::Low, Pull::Up),
+        o3: OutputOpenDrain::new(io.pins.gpio8, Level::Low, Pull::Up),
+        o4: OutputOpenDrain::new(io.pins.gpio10, Level::Low, Pull::Up),
+    };
 
     let mut ctx = Context {
         button_pressed: None,
@@ -197,101 +177,62 @@ pub enum Button {
 pub struct Context {
     button_pressed: Option<Button>,
 }
-
-struct Rows<'d> {
-    gpio2: Input<'d, Gpio2>, //
-    gpio3: Input<'d, Gpio3>, //
-    gpio4: Input<'d, Gpio4>, //
-    gpio5: Input<'d, Gpio5>, //
+struct Keypad<'d> {
+    o1: OutputOpenDrain<'d, Gpio6>,  //
+    o2: OutputOpenDrain<'d, Gpio7>,  //
+    o3: OutputOpenDrain<'d, Gpio8>,  //
+    o4: OutputOpenDrain<'d, Gpio10>, //
+    // --------------------------------------
+    i1: Input<'d, Gpio2>, //
+    i2: Input<'d, Gpio3>, //
+    i3: Input<'d, Gpio4>, //
+    i4: Input<'d, Gpio5>, //
 }
-struct Cols<'d> {
-    gpio6: OutputOpenDrain<'d, Gpio6>,   //
-    gpio7: OutputOpenDrain<'d, Gpio7>,   //
-    gpio8: OutputOpenDrain<'d, Gpio8>,   //
-    gpio10: OutputOpenDrain<'d, Gpio10>, //
-}
-pub type OOD<'d, T> = OutputOpenDrain<'d, T>;
-
-struct Keypad<'d>(
-    pub  (
-        // --------------------------------------
-        (&'d mut Input<'d, Gpio2>, &'d mut OOD<'d, Gpio6>),
-        (&'d mut Input<'d, Gpio3>, &'d mut OOD<'d, Gpio6>),
-        (&'d mut Input<'d, Gpio4>, &'d mut OOD<'d, Gpio6>),
-        (&'d mut Input<'d, Gpio5>, &'d mut OOD<'d, Gpio6>),
-        // --------------------------------------
-        (&'d mut Input<'d, Gpio2>, &'d mut OOD<'d, Gpio7>),
-        (&'d mut Input<'d, Gpio3>, &'d mut OOD<'d, Gpio7>),
-        (&'d mut Input<'d, Gpio4>, &'d mut OOD<'d, Gpio7>),
-        (&'d mut Input<'d, Gpio5>, &'d mut OOD<'d, Gpio7>),
-        // --------------------------------------
-        (&'d mut Input<'d, Gpio2>, &'d mut OOD<'d, Gpio8>),
-        (&'d mut Input<'d, Gpio3>, &'d mut OOD<'d, Gpio8>),
-        (&'d mut Input<'d, Gpio4>, &'d mut OOD<'d, Gpio8>),
-        (&'d mut Input<'d, Gpio5>, &'d mut OOD<'d, Gpio8>),
-        // --------------------------------------
-        (&'d mut Input<'d, Gpio2>, &'d mut OOD<'d, Gpio10>),
-        (&'d mut Input<'d, Gpio3>, &'d mut OOD<'d, Gpio10>),
-        (&'d mut Input<'d, Gpio4>, &'d mut OOD<'d, Gpio10>),
-        (&'d mut Input<'d, Gpio5>, &'d mut OOD<'d, Gpio10>),
-    ),
-);
 impl<'d> Keypad<'d> {
     pub fn pressed(&mut self) -> Option<Button> {
-        let col1 = [
-            self.0 .0.is_low(),
-            self.0 .1.is_low(),
-            self.0 .2.is_low(),
-            self.0 .3.is_low(),
-        ];
-        let col2 = [
-            self.0 .4.is_low(),
-            self.0 .5.is_low(),
-            self.0 .6.is_low(),
-            self.0 .7.is_low(),
-        ];
-        let col3 = [
-            self.0 .8.is_low(),
-            self.0 .9.is_low(),
-            self.0 .10.is_low(),
-            self.0 .11.is_low(),
-        ];
-        let col4 = [
-            self.0 .12.is_low(),
-            self.0 .13.is_low(),
-            self.0 .14.is_low(),
-            self.0 .15.is_low(),
-        ];
+        let res: [[bool; 4]; 4] = core::array::from_fn(|x| {
+            core::array::from_fn(|y| {
+                self.set_high(x as u8);
+                let v = self.is_low(y as u8);
+                self.set_low(x as u8);
+                v
+            })
+        });
 
-        if col1.iter().any(|b| !b)
-            || col2.iter().any(|b| !b)
-            || col3.iter().any(|b| !b)
-            || col4.iter().any(|b| !b)
-        {
+        if res.iter().any(|a| a.iter().any(|b| !b)) {
             println!("***************************************");
-            println!("col1 {col1:?}");
-            println!("col2 {col2:?}");
-            println!("col3 {col3:?}");
-            println!("col4 {col4:?}");
+            for a in res {
+                println!("col {a:?}");
+            }
         }
         None
     }
-}
 
-trait KeyboardInput<'d> {
-    fn is_low(&mut self) -> bool;
-    fn is_high(&mut self) -> bool {
-        !self.is_low()
-    }
-}
-
-impl<'d, C: InputPin, R: OutputPin + InputPin> KeyboardInput<'d>
-    for (&'d mut Input<'d, C>, &'d mut OutputOpenDrain<'d, R>)
-{
-    fn is_low(&mut self) -> bool {
-        self.1.set_low();
-        let s = self.0.is_low();
-        self.1.set_high();
-        s
+    fn set_high(&mut self, o: u8) {
+        match o {
+            0 => self.o1.set_high(),
+            1 => self.o2.set_high(),
+            2 => self.o3.set_high(),
+            3 => self.o4.set_high(),
+            _ => {}
+        };
+    }
+    fn set_low(&mut self, o: u8) {
+        match o {
+            0 => self.o1.set_low(),
+            1 => self.o2.set_low(),
+            2 => self.o3.set_low(),
+            3 => self.o4.set_low(),
+            _ => {}
+        };
+    }
+    fn is_low(&mut self, o: u8) -> bool {
+        match o {
+            0 => self.i1.is_low(),
+            1 => self.i2.is_low(),
+            2 => self.i3.is_low(),
+            3 => self.i4.is_low(),
+            _ => false,
+        }
     }
 }