which will draw this:  ``` 0 OK, 10:2 ``` *Fig. 14 – Arc drawn with DRAW statement* When run on *Layer 0*, the drawing starts off in a south-easterly direction, but by the time it stops it is going north-west: in between it has turned round through **180** degrees, or π radians (the value of **a**). Obviously, when run on other layers, the vertical part of the drawing is inverted in line with everything we have discussed. Run the program several times, with **PI** replaced by various other expressions e.g. **-PI**, **PI/2**, **3\*PI/2**, **PI/4**, **1,0**. > **Notes** > > Due to the way values are calculated, it's not advisable to use values exceeding π for the *arc_turn* parameter as they may not perform in the way you would intend. That being said there are various values that produce very interesting results. Try: > > ``` > PLOT 75,75: DRAW 80, 24, x > ``` > > where **x** is **400**, **600** or **800**. Experiment further to see what other effects you can generate. The last statement in this section is the **CIRCLE** statement, which draws an entire circle. You specify the coordinates of the centre and the radius of the circle using: **CIRCLE** *x_coordinate*, *y_coordinate*, *radius* Just as with **PLOT** and **DRAW**, you can put the various sorts of colour items in at the beginning of a **CIRCLE** statement. As with its **PLOT** and **DRAW** counterparts, **CIRCLE**, when used in *Layer 0* will produce an error for circles drawn out of bounds but the remaining layers will happily draw off-screen. ### POINT, POINT TO The **POINT** function informs you of the contents of a pixel on screen. It accepts two parameters enclosed in parentheses, *x_coordinate* and *y_coordinate*. **POINT** on its own works only on *Layer 0* and returns **1** if the pixel is set or **0** if not set. Whilst in *Layer 0* try: ``` CLS: PRINT POINT (0,0): PLOT 0,0 :PRINT POINT (0,0) ``` There's an extended variant of **POINT** utilising the **TO** modifier which works on *all* layers, that takes the output of **POINT** and stores it in variable *var*. This returns **1** if the pixel is set or **0** if not set in all layers except *LoRes* and *Layer2* just as the plain **POINT** does. In *LoRes* and *Layer 2* however, it returns a value from **0** to **255** which is the actual palette index entry