fix lint

example/FluidMotion/dart/FluidMotion.dart

diff --git a/example/FluidMotion/dart/FluidMotion.dart b/example/FluidMotion/dart/FluidMotion.dart
index d01e765..d638035 100644
--- a/example/FluidMotion/dart/FluidMotion.dart
+++ b/example/FluidMotion/dart/FluidMotion.dart
@@ -354,14 +354,14 @@
       for (var i = 1; i <= width; i++) {
         var x = i - Wdt0 * u[++pos];
         var y = j - Hdt0 * v[pos];
-        if (x < 0.5)
+        if (x < 0.5) {
           x = 0.5;
-        else if (x > Wp5) x = Wp5;
+        } else if (x > Wp5) x = Wp5;
         var i0 = x.toInt();
         var i1 = i0 + 1;
-        if (y < 0.5)
+        if (y < 0.5) {
           y = 0.5;
-        else if (y > Hp5) y = Hp5;
+        } else if (y > Hp5) y = Hp5;
         var j0 = y.toInt();
         var j1 = j0 + 1;
         var s1 = x - i0;