diff --git a/DLASystem.cpp b/DLASystem.cpp
index 490927f..75cf08d 100644
--- a/DLASystem.cpp
+++ b/DLASystem.cpp
@@ -167,7 +167,7 @@ void DLASystem::moveLastParticle() {
         setGrid(lastP->pos, 1);  // set the new grid site to be occupied
 
         // check if we stick
-        if (checkStick()) {
+        if (checkStick() && this->rgen.random01() <= this->stickProbability) {
             this->csv_out << frame << "," << lastP->pos[0] << "," << lastP->pos[1] << endl;
             setParticleInactive();  // make the particle inactive (stuck)
             updateClusterRadius(lastP->pos);  // update the cluster radius, addCircle, etc.
@@ -197,16 +197,17 @@ int DLASystem::checkStick() {
 
 
 // constructor
-DLASystem::DLASystem(std::ofstream csv_out) {
+DLASystem::DLASystem(std::ofstream csv_out, double stickProbability)
+        : stickProbability(stickProbability), csv_out(std::move(csv_out)) {
     cout << "creating system, gridSize " << gridSize << endl;
     endNum = 1000;
-    this->csv_out = std::move(csv_out);
 
     // allocate memory for the grid, remember to free the memory in destructor
     grid = new int *[gridSize];
     for (int i = 0; i < gridSize; i++) {
         grid[i] = new int[gridSize];
     }
+
     // reset initial parameters
     Reset();
 
diff --git a/DLASystem.h b/DLASystem.h
index 3fa3d56..22b1421 100644
--- a/DLASystem.h
+++ b/DLASystem.h
@@ -30,6 +30,8 @@ private:
     double addCircle;
     double killCircle;
 
+    double stickProbability;
+
     // size of grid
     static const int gridSize = 1600;
     int **grid;  // this will be a 2d array that stores whether each site is occupied
@@ -64,7 +66,7 @@ public:
     int lastParticleIsActive;
 
     // constructor
-    DLASystem(std::ofstream csv_out);
+    DLASystem(std::ofstream csv_out, double stickProbability);
 
     // destructor
     ~DLASystem();
diff --git a/mainDLA.cpp b/mainDLA.cpp
index 740580d..9e7437f 100644
--- a/mainDLA.cpp
+++ b/mainDLA.cpp
@@ -16,7 +16,7 @@ int main(int argc, char **argv) {
     std::ofstream csv_out("./out.csv");
 
     // create the system
-    sys = new DLASystem(std::move(csv_out));
+    sys = new DLASystem(std::move(csv_out), 0.5);
 
     // this is the seed for the random numbers
     int seed = 6;