diff --git a/client/client.ino b/client/client.ino
index b6f4bd0..fd6cc33 100644
--- a/client/client.ino
+++ b/client/client.ino
@@ -3,6 +3,7 @@
 #include <Adafruit_ST7735.h>
 #include <ESP8266WiFi.h>
 #include <ESP8266HTTPClient.h>
+#include <memory>
 #include <SPI.h>
 #include <WiFiClientSecureBearSSL.h>
 
@@ -46,44 +47,144 @@
 #define STATUS_WIDTH (10 * CX)
 #define STATUS_HEIGHT CY
 
+// Function definitions
+
+void drawLayout();
+uint16_t rgb(uint16_t, uint16_t, uint16_t);
+String fetchDepartures();
+
 // Peripherals
 
 Adafruit_ST7735 display(TFT_CS, TFT_DC, TFT_RESET);
 
-// App state
+// App state interface
 
-typedef enum {
-  CONNECTING,
-  SHOWING_DEPARTURES
-} State;
+class State {
+public:
+  virtual void enter() = 0;
+  virtual void tick() = 0;
+  virtual ~State() = default;
+};
 
-State state = CONNECTING;
-State previous_state = state;
-int frame = 0;
-// Use this variable to trigger state enter effects
-int state_changed = 1;
+class StateConnecting : public State {
+public:
+  void enter() override;
+  void tick() override;
+};
+
+class StateFetching : public State {
+public:
+  void enter() override;
+  void tick() override;
+};
+
+class StateShowingDepartures : public State {
+private:
+  // Todo: discard JsonDocument asap, parse into better format
+  JsonDocument departures;
+  unsigned long entered;
+public:
+  StateShowingDepartures(String&);
+  void enter() override;
+  void tick() override;
+};
+
+// App state implementation
+
+uint64_t currentTick = 0;
+// Initially true so that enter() of the initial state is called.
+bool stateChanged = true;
+std::unique_ptr<State> state = std::make_unique<StateConnecting>();
+
+template <typename StateType, typename... Args>
+void setState(Args&&... args) {
+  state = std::make_unique<StateType>(std::forward<Args>(args)...);
+  stateChanged = true;
+}
+
+void StateConnecting::enter() {
+  Serial.println("Entering StateConnecting");
+}
+
+void StateConnecting::tick() {
+  if (WiFi.status() != WL_CONNECTED) {
+    display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
+    display.setCursor(STATUS_X, STATUS_Y);
+    display.printf(" connect %c", "|/-\\"[currentTick % 4]);
+    delay(250);
+    return;
+  }
+
+  setState<StateFetching>();
+}
+
+// Fetching is a bit of an ugly duckling; it performs all its logic in enter().
+// This is because request it does is synchronous.
+// Sadly this means no animation is possible right now.
+// At least the fetch call still does yield() under the hood :)
+void StateFetching::enter() {
+  Serial.println("Entering StateFetching");
+
+  if (WiFi.status() != WL_CONNECTED) {
+    setState<StateConnecting>();
+    return;
+  }
+
+  display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
+  display.setCursor(STATUS_X, STATUS_Y);
+  display.print("  fetching");
+  
+  String departuresRaw = fetchDepartures();
+  
+  setState<StateShowingDepartures>(departuresRaw);
+};
+
+void StateFetching::tick() {
+}
+
+StateShowingDepartures::StateShowingDepartures(String &departuresRaw) {
+  deserializeJson(departures, departuresRaw);
+}
+
+void StateShowingDepartures::enter() {
+  Serial.println("Entering StateShowingDepartures");
+  entered = millis();
+
+  display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
+  display.fillRect(MAIN_X, MAIN_Y, MAIN_WIDTH, MAIN_HEIGHT, COLOR_BG);
+
+  int line = 0;
+  for (JsonVariant departure : departures["departures"].as<JsonArray>()) {
+    display.setCursor(MAIN_X, MAIN_Y + (CY + 3) * line);
+    display.printf("%2s %-15.15s ",
+      departure["symbol"].as<const char*>(),
+      departure["direction"].as<const char *>()
+    );
+    if (departure["leaving"].as<String>().equals("sofort")) {
+      int16_t x = display.getCursorX();
+      int16_t y = display.getCursorY();
+      display.drawBitmap(x + 6 * CX - tiny_train_dims[0], y, tiny_train[0], tiny_train_dims[0], tiny_train_dims[1], COLOR_TEXT);
+    } else {
+      display.printf("%6s", departure["leaving"].as<const char*>());
+    }
+
+    line++;
+  }
+}
+
+void StateShowingDepartures::tick() {
+  unsigned long elapsed = millis() - entered;
+  if (elapsed > 25000) {
+    setState<StateFetching>();
+  }
+}
 
 int buttonPushed = false;
-JsonDocument departures;
 
 void ICACHE_RAM_ATTR onButtonFalling() {
   buttonPushed = true;
 }
 
-uint16_t rgb(uint16_t r, uint16_t g, uint16_t b) {
-  // Color layout: RRRRRGGGGGGBBBBB (5, 6, 5)
-  return ((b >> 3) & 0b11111) << 11 | ((g >> 2) & 0b111111) << 5 | ((r >> 3) & 0b11111);
-}
-
-void drawLayout() {
-  display.fillScreen(COLOR_BG);
-  display.drawFastHLine(5, 4, 150, COLOR_DIVIDER);
-  display.drawFastHLine(5, 109, 150, COLOR_DIVIDER);
-  display.drawFastHLine(5, 123, 150, COLOR_DIVIDER);
-  display.setCursor(CLOCK_X, CLOCK_Y);
-  display.print("13:12");
-}
-
 void setup() {
   Serial.begin(9600);
 
@@ -102,10 +203,39 @@ void setup() {
   
   pinMode(BUTTON_PIN, INPUT_PULLUP);
   attachInterrupt(BUTTON_PIN, onButtonFalling, FALLING);
+
+  state = std::make_unique<StateConnecting>();
 }
 
 #define QUERY_STRING "stop_id=de:08221:1225&platform=A"
 
+void loop() {
+  if (stateChanged) {
+    stateChanged = false;
+    // Note: enter() may call setState(). In that case we want to end up right back here.
+    state->enter();
+  } else {
+    state->tick();
+    currentTick++;
+  }
+  // Let background system do its thing
+  yield();
+}
+
+uint16_t rgb(uint16_t r, uint16_t g, uint16_t b) {
+  // Color layout: RRRRRGGGGGGBBBBB (5, 6, 5)
+  return ((b >> 3) & 0b11111) << 11 | ((g >> 2) & 0b111111) << 5 | ((r >> 3) & 0b11111);
+}
+
+void drawLayout() {
+  display.fillScreen(COLOR_BG);
+  display.drawFastHLine(5, 4, 150, COLOR_DIVIDER);
+  display.drawFastHLine(5, 109, 150, COLOR_DIVIDER);
+  display.drawFastHLine(5, 123, 150, COLOR_DIVIDER);
+  display.setCursor(CLOCK_X, CLOCK_Y);
+  display.print("13:12");
+}
+
 // TODO: Error handling
 String fetchDepartures() {
   std::unique_ptr<BearSSL::WiFiClientSecure> https(new BearSSL::WiFiClientSecure);
@@ -131,69 +261,3 @@ String fetchDepartures() {
 
   return client.getString();
 }
-
-void loop() {
-  if (state != previous_state) {
-    state_changed = 1;
-    previous_state = state;
-  }
-  logic_loop();
-  frame++;
-  state_changed = 0;
-}
-
-void logic_loop() {
-  switch (state) {
-    case CONNECTING: {
-      if (WiFi.status() != WL_CONNECTED) {
-        display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
-        display.setCursor(STATUS_X, STATUS_Y);
-        display.printf(" connect %c", "|/-\\"[frame % 4]);
-        delay(FRAME_DELAY);
-        return;
-      }
-
-      display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
-      display.setCursor(STATUS_X, STATUS_Y);
-      display.print("  fetching");
-
-      String departuresRaw = fetchDepartures();
-      deserializeJson(departures, departuresRaw);
-      
-      state = SHOWING_DEPARTURES;
-      frame = 0;
-      return;
-    }
-      
-    case SHOWING_DEPARTURES:
-      if (WiFi.status() != WL_CONNECTED) {
-        state = CONNECTING;
-        return;
-      }
-
-      display.fillRect(STATUS_X, STATUS_Y, STATUS_WIDTH, STATUS_HEIGHT, COLOR_BG);
-      display.fillRect(MAIN_X, MAIN_Y, MAIN_WIDTH, MAIN_HEIGHT, COLOR_BG);
-
-      int line = 0;
-      for (JsonVariant departure : departures["departures"].as<JsonArray>()) {
-        display.setCursor(MAIN_X, MAIN_Y + (CY + 3) * line);
-        display.printf("%2s %-15.15s ",
-          departure["symbol"].as<const char*>(),
-          departure["direction"].as<const char *>()
-        );
-        if (departure["leaving"].as<String>().equals("sofort")) {
-          int16_t x = display.getCursorX();
-          int16_t y = display.getCursorY();
-          display.drawBitmap(x + 6 * CX - tiny_train_dims[0], y, tiny_train[0], tiny_train_dims[0], tiny_train_dims[1], COLOR_TEXT);
-        } else {
-          display.printf("%6s", departure["leaving"].as<const char*>());
-        }
-
-        line++;
-      }
-      
-      delay(25000);
-      state = CONNECTING;
-      return;
-  }
-}