I believe this is a more robust solution to the set helper

src/play.rs

@@ -64,7 +64,7 @@ pub(crate) fn reset_rotation(
 
 /// Check a set when the "Set" button is clicked
 pub(crate) fn check_set(
-    trigger: Trigger<Pointer<Click>>,
+    _trigger: Trigger<Pointer<Click>>,
     mut query: Query<(Entity, &Card, &mut Visibility, &mut Transform), With<Selected>>,
     mut commands: Commands,
 ) {
@@ -205,47 +205,49 @@ pub(crate) fn check_for_sets(
     _trigger: Trigger<Pointer<Click>>,
     cards: Query<(Entity, &Card), With<PlayLocation>>,
     selected: Query<Entity, With<Selected>>,
-    mut help_set: Local<Option<(Entity, Entity, Entity)>>,
     mut commands: Commands,
 ) {
-    match *help_set {
-        None => {
-            *help_set = cards
+    cards
+        // Iterate over all combinations of cards on the board
         .iter_combinations()
+        // Only find combinations including currently selected cards
+        .filter(|[(ea, _ca), (eb, _cb), (ec, _cc)]| {
+            // If selected is empty, proceed
+            match selected.iter().len() {
+                0 => true,
+                1 | 2 | 3 => {
+                    let a = selected.contains(*ea);
+                    let b = selected.contains(*eb);
+                    let c = selected.contains(*ec);
+                    match selected.iter().len() {
+                        1 => a || b || c,
+                        2 => a && b || b && c || a && c,
+                        3 => a && b && c,
+                        _ => panic!("WTF?"),
+                    }
+                }
+                _ => panic!("Impossible!"),
+            }
+        })
+        // return the first valid set
         .find_map(|[(ea, ca), (eb, cb), (ec, cc)]| {
-                    (is_set((ca, cb, cc))).then_some((ea, eb, ec))
-                });
-        }
-        Some((a, b, c)) => {
-            if cards.get_many([a, b, c]).is_err() {
-                *help_set = cards
-                    .iter_combinations()
-                    .find_map(|[(ea, ca), (eb, cb), (ec, cc)]| {
-                        (is_set((ca, cb, cc))).then_some((ea, eb, ec))
-                    });
-            }
-        }
+            if is_set((ca, cb, cc)) {
+                info!("\n\t{}\n\t{}\n\t{}", ca, cb, cc);
+                Some((ea, eb, ec))
+            } else {
+                None
             }
-
-    // TODO: Check if help_set cards are all still on board, if not set to None
-
-    help_set.iter().for_each(|(a, b, c)| {
-        match (
-            selected.contains(*a),
-            selected.contains(*b),
-            selected.contains(*c),
-        ) {
-            (false, false, false) => {
+        })
+        .iter()
+        .for_each(|(a, b, c)| {
+            if !selected.contains(*a) {
                 commands.entity(*a).insert(Selected);
-            }
-            (true, false, false) => {
+            } else if !selected.contains(*b) {
                 commands.entity(*b).insert(Selected);
-            }
-            (true, true, false) => {
+            } else if !selected.contains(*c) {
                 commands.entity(*c).insert(Selected);
-            }
-            (true, true, true) => info!("I can't hold your hand any further."),
-            _ => panic!("How???"),
+            } else {
+                info!("I cannot hold your hand further...");
             }
         });
 }