bezier(85, 20, 10, 10, 90, 90, 15, 80); 
ellipseMode(CENTER_DIAMETER); 
int steps = 6; 
for (int i = 0; i <= steps; i++) { 
  float t = i / float(steps); 
  // Get the location of the point 
  float x = bezierPoint(85, 10, 90, 15, t); 
  float y = bezierPoint(20, 10, 90, 80, t); 
  // Get the tangent points 
  float tx = bezierTangent(85, 10, 90, 15, t); 
  float ty = bezierTangent(20, 10, 90, 80, t); 
  // Calculate an angle from the tangent points 
  float a = atan2(ty, tx); 
  stroke(255, 102, 0); 
  line(x, y, cos(a)*30 + x, sin(a)*30 + y); 
  // This follwing line of code makes a line 
  // inverse of the above line 
  //line(x, y, cos(a)*-30 + x, sin(a)*-30 + y); 
  stroke(0); 
  ellipse(x, y, 5, 5); 
} 

bezier(85, 20, 10, 10, 90, 90, 15, 80); 
stroke(255, 102, 0); 
int steps = 16; 
for (int i = 0; i <= steps; i++) { 
  float t = i / float(steps); 
  float x = bezierPoint(85, 10, 90, 15, t); 
  float y = bezierPoint(20, 10, 90, 80, t); 
  float tx = bezierTangent(85, 10, 90, 15, t); 
  float ty = bezierTangent(20, 10, 90, 80, t); 
  float a = atan2(ty, tx); 
  a += PI/2.0; 
  line(x, y, cos(a)*8 + x, sin(a)*8 + y); 
}