Index: src/solver.d
==================================================================
--- src/solver.d
+++ src/solver.d
@@ -303,10 +303,11 @@
 }
 
 class Solver_2(Solver)
 {
 	string plan;
+	bool plan_broken = true;
 
 	Game g;
 	this(in Game g)
 	{
 		this.g = g.clone();
@@ -327,10 +328,11 @@
 			log.length--;
 		return tuple(s, log);
 	}
 
 	void make_plan(in Game g) {
+		plan_broken = false;
 		Tuple!(Solver,string) x = run_sub_solver(g);
 		plan = x[1];
 		if(x[0].g.cleared)
 			return;
 		modify_plan(g, x[0].g.score);
@@ -362,10 +364,12 @@
 		Tuple!(Solver, string) x = run_sub_solver(gg);
 		return tuple(x[1], x[0].g.score);
 	}
 
 	char single_step() {
+		if(plan_broken)
+			make_plan(g);
 		if(plan.empty)
 			return 'A';
 		char c = plan[0];
 		plan = plan[1..$];
 		g.command(c);
@@ -372,11 +376,16 @@
 		return c;
 	}
 
 	void force(char c) {
 		g.command(c);
-		make_plan(g);
+		if(plan.length==0 || plan[0]!=c) {
+			plan = "";
+			plan_broken = true;
+		}
+		else
+			plan = plan[1..$];
 	}
 }
 
 alias Solver_2!(Solver_1) MainSolver;
 //alias Solver_1 MainSolver;