diff --git a/hosts/common.nix b/hosts/common.nix
index d16f24b..5b3aaa5 100644
--- a/hosts/common.nix
+++ b/hosts/common.nix
@@ -152,17 +152,17 @@ in {
       };
     };
 
-    shellAliases.fixDisplay = let
+    shellAliases.fixdisplay = let
       inherit (config.machineVars) screens headless fixDisplayCommand;
 
-      screenToArgs = screen: with screen;
-        "--output ${name} --mode ${resolution}"
-        + (lib.optionalString (frequency != null) " --rate ${frequency}");
+      screenToArgs = name: screen: with screen;
+        "--output ${name} --mode ${resolution} --rate ${toString frequency} --pos ${position}"
+        + (lib.optionalString primary " --primary");
 
       screenArgs = lib.concatStringsSep " " (lib.mapAttrsToList screenToArgs screens);
 
     in lib.mkIf (!headless)
-      (if screenArgs == null
+      (if screenArgs != null
           then "xrandr ${screenArgs}"
           else (lib.mkIf (fixDisplayCommand != null) fixDisplayCommand));
   };
@@ -305,6 +305,7 @@ in {
     light.enable = !config.machineVars.headless;
     npm.enable = true;
     tmux.enable = true;
+    zsh.enable = true;
 
     gnupg.agent = {
       enable = true;
diff --git a/hosts/eisei/configuration.nix b/hosts/eisei/configuration.nix
index 4feb9f6..100a0ad 100644
--- a/hosts/eisei/configuration.nix
+++ b/hosts/eisei/configuration.nix
@@ -20,11 +20,7 @@ in {
     headless = false;
     laptop = true;
 
-    screens = {
-      "eDP-1" = {
-        resolution = "1920x1080";
-      };
-    };
+    screens."eDP-1".primary = true;
   };
 
   systemd.targets = {
diff --git a/hosts/kasei/configuration.nix b/hosts/kasei/configuration.nix
index 60b6729..a50a2ff 100644
--- a/hosts/kasei/configuration.nix
+++ b/hosts/kasei/configuration.nix
@@ -25,12 +25,15 @@
       default = main;
     };
 
-    fixDisplayCommand = "xrandr --output DP-4 --mode 1920x1080 --pos 0x0 -r 144 --output HDMI-0 --primary --mode 1920x1080 --pos 1920x0 -r 60";
-
-    # screens = {
-    #   "DP-1" = {};
-    #   "HDMI-1" = {};
-    # };
+    screens = {
+      DP-4 = {
+        primary = true;
+        frequency = 144;
+      };
+      HDMI-0 = {
+        position = "1920x0";
+      };
+    };
   };
 
   systemd.targets = {
diff --git a/modules/machineVars.nix b/modules/machineVars.nix
index 57764dd..a083bd3 100644
--- a/modules/machineVars.nix
+++ b/modules/machineVars.nix
@@ -9,12 +9,6 @@ in {
     screens = mkOption {
       type = types.attrsOf (types.submodule ( { name, ...}: {
         options = {
-          resolution = mkOption {
-            type = types.str;
-            example = "1920x1080";
-            description = "The resolution of the screen";
-          };
-
           name = mkOption {
             type = types.str;
             default = name;
@@ -22,11 +16,28 @@ in {
             description = "The name of the screen";
           };
 
-          freq = mkOption {
-            type = types.nullOr types.str;
-            example = "60.00";
+          primary = mkEnableOption "Whether this screen should be the primary one. There can only be one primary screen";
+
+          resolution = mkOption {
+            type = types.str;
+            example = "3840x2160";
+            default = "1920x1080";
+            description = "The resolution of the screen";
+          };
+
+          frequency = mkOption {
+            type = types.ints.positive;
+            example = 144;
+            default = 60;
             description = "The update frequency of the screen, defined in Hz";
           };
+
+          position = mkOption {
+            type = types.str;
+            example = "1920x0";
+            default = "0x0";
+            description = "The position of the screen, compared to the other screens";
+          };
         };
       }));
       default = { };
@@ -102,6 +113,11 @@ t tools preinstalled.";
         assertion = cfg.battery != null -> cfg.laptop;
         message = "A battery shouldn't exist on a non laptop machine";
       }
+      # FIXME:
+      # {
+      #   assertion = map () (cfg.screens)
+      #   message = "There can only be one primary screen.";
+      # }
     ];
 
     warnings = lib.optionals (0 < (lib.length (builtins.attrNames cfg.screens)) && (cfg.fixDisplayCommand != null)) [