# Turtles

## Building Turtles

```(turtle-new image)```
MediaScheme Turtle Constructor. Build a new turtle that draws on `image`.
```(turtle-clone turtle)```
MediaScheme Turtle Constructor. Make a clone of `turtle` (same position, direction, color, brush, etc.).

## Moving Turtles

```(turtle-forward! turtle distance)```
MediaScheme Turtle Procedure. Moves `turtle` forward by the specified distance.
```(turtle-teleport! turtle col row)```
MediaScheme Turtle Procedure. Move `turtle` to (`col`,`row`). Do not draw along the way.
```(turtle-face! turtle angle)```
MediaScheme Turtle Procedure. Make `turtle` face the diretion specified by `angle` (clockwise from right).
```(turtle-turn! turtle angle)```
MediaScheme Turtle Procedure. Rotate `turtle` clockwise by `angle` degrees.

## Drawing with Turtles

```(turtle-down! turtle)```
MediaScheme Turtle Procedure. Put `turtle`'s brush down. When the turtle moves forward, it draws with the brush.
```(turtle-up! turtle)```
MediaScheme Turtle Procedure. Lifts `turtle`'s brush. When `turtle` moves forward, it will not draw.
```(turtle-set-brush! turtle brush)```
MediaScheme Turtle Procedure. Set the brush that `turtle` draws with.
```(turtle-set-color! turtle color)```
MediaScheme Turtle Procedure. Set the color in which `turtle` draws.

## Miscellaneous Turtle Procedures

```(turtle-world turtle)```
MediaScheme Turtle Procedure. Determine the world on which `turtle` resides.

Samuel A. Rebelsky, rebelsky@grinnell.edu

Copyright (c) 2007-10 Janet Davis, Matthew Kluber, Samuel A. Rebelsky, and Jerod Weinman. (Selected materials copyright by John David Stone and Henry Walker and used by permission.)

This material is based upon work partially supported by the National Science Foundation under Grant No. CCLI-0633090. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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