Instructions for circles

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In this task you will define the following functions:

• concentricCircles
• multicolorCircles

Your circles.py file should begin with this header, which you should paste into the file and fill out (as usual, each function you write must be documented):

"""
Authors:
Consulted:
Date:
Purpose: CS 111 circles task: draws concentric circles in alternating
colors.
"""

from turtleBeads import *
from turtle import *

Part A: concentricCircles

In this subtask, your goal is to generate pictures like those shown in these examples for concentricCircles, consisting of multiple concentric circles of alternating colors that form a bullseye pattern.

Define the concentricCircles function such that:

1. It draws a series of concentric circles, where the first parameter specifies the radius of the outermost circle, and the second parameter specifies the number of circles to draw.
2. The third and fourth parameters specify an outer color and an other color, respectively. The outer color is used for the largest (i.e., outermost) circle, and then every other circle in from the edge alternates between that color and the 'other' color.
3. All rings have the same thickness, and the radius of the innermost circle is equal to that thickness. Put another way, the radius of each circle is a multiple of the radius of the innermost dot. For example if the total radius is 100 and there are 4 circles, their radii will be 25, 50, 75, and 100.

Notes

• Read the rules above carefully, to determine how to calculate the radius of the largest and smallest circles, as well as every radius in between.
• The "outer" color is always used to color the outermost circle.
• You must use either a for loop or a while loop to draw the circles.
• The order in which the circles are drawn matters, because whatever is drawn later covers stuff drawn earlier.
• For this function, we recommend that you create an iteration table (see the lecture on while loops to plan out your strategy for solving it.
• You must use the turtleBeads drawDot function (reference for drawDot) to draw your circles, rather than using the turtle circle function or the turtleBeads drawCircle function, because we will grade based on whether your calls to drawDot are correct. drawDot works just like drawCircle, except that it is much faster, the circle it draws is always filled in, and it uses the pen color, not the fill color (this also means you don't need to call begin_fill and end_fill).

Testing

You can test your concentricCircles function by executing the example code in the shell. We recommend using noTrace beforehand and showPicture afterwards to speed things up. We have also supplied a test_circles.py file that draws four circles and uses optimism to check that the printed output is correct.

Part B: multicolorCircles

For this part, you will create a multicolorCircles function that uses a (possibly nested) loop to draw concentric circles using an arbitrary number of colors. These multicolorCircles examples show how it should work.

multicolorCircles must accept 3 parameters:

1. A base radius, which will be the radius of the smallest circle (this is different from concentricCircles above). The second-smallest circle will have twice this radius, the third-smallest three times this radius, and so on.
2. A list of strings indicating colors to use in succession, starting from the outermost circle.
3. A positive integer specifying the number of cycles to complete, where a single cycle involves using each color from the list of colors once.

Notes

• Because each cycle uses every color from the list, the total number of circles will be equal to the length of the colors list times the number of cycles. You may assume that the cycles argument will always be an integer, which implies that every multicolored circle pattern will have one or more complete copies of the color cycle, never partial copies.
• Hint: just like with strings, you can multiply a list by an integer to create a longer list containing multiple repetitions of the initial list.
• Whereas for concentricCircles you were given the outermost radius as an argument, in multicolorCircles you are given the innermost radius. This value is also the difference between the radii of each successive circle, so for example, if the value was 10 and there were 3 circles, their radii would be 10, 20, and 30.
• There are multiple viable approaches to this problem, including two loops after each other, just one loop, or two loops inside each other.
• As with concentricCircles, you must use the turtleBeads drawDot function to draw your circles, rather than using the turtle circle function or the turtleBeads drawCircle function, because we will grade based on whether your calls to drawDot are correct.