# Tag raise

#### Logo Fireworks

This Logo program uses hatchlings to create simple 2D fireworks. The turtle’s model is changed into an icosphere to simulate a launching firework, and then more hatchlings are used to create the starburst. The trails are merged back into the main turtle ‘track’ and the hatchlings are terminated, leaving the rendered drawing on-screen at the conclusion of the program.

Read through the code (and pay particular attention to the ;comments) to see how the program works. It is made up of two procedures: fireworks, and burst.

```TO fireworks
;simple 2D fireworks

reset
hideturtle

repeat 5 + random 10 [
;launch at least 5 but not more
;than 14 fireworks

penup
;pull up the turtle's pen

home

raise repcount
;raise the turtle so its lines
;don't overlap

sety -100
;set the turtle's y position to
;-100

hatch [left -60 + random 121 burst]
;hatch a new turtle, turn that
;turtle left some random value
;between -60 (same as right 60)
;and 60 degrees, then execute the
;burst procedure

wait 30 + random 31
;wait between one half and one
;second before launching the next
]
;repeat until all fireworks launched

END

TO burst
;a single firework 'burst'
;originally called 'firwork' but
;that was a little confusing!

penup hideturtle

newmodel "firework [icosphere 1]
setmodel "firework
;create and use a simple model

randomfillcolor
;set a random fill color
;models inherit the fill color
;if not otherwise set inside
;the model

showturtle

repeat 100 + random 601 [
;travel between 200 and 700
;turtle steps

forward 1 - 0.002 * repcount
;move forward 1 step minus
;a fraction based on the current
;loop iteration. This has the
;effect of slowing us down
;over time (reduce velocity)

sety ypos - 0.0005 * repcount
;change the y position of the
;turtle a fraction based on the
;current loop iteration, simulating
;very simple gravity

sleep 2
;take a little nap

]
;repeat until finished travelling

setpencolor fillcolor
;set the pen color to the fill color

hideturtle

repeat 20 + random 21 [
;create between 20 and 40 fragments

raise 0.01
;ensures seperation between
;overlapping lines

hatch [
pendown
;draw lines

right random 360
;turn right between 0 and 359
;degrees

make "steps 30 + random 71
repeat :steps [
;travel between 30 and 100
;turtle steps

;setpenshade -15 + repcount / 5
setpenshade -15 + 30 * (repcount / :steps)
;set the pen shade based on the
;loop iterations

fd 1 - 0.002 * repcount
;move forward minus "drag"

sety ypos - 0.01 * repcount
;apply fake gravity

]
merge
;merge the hatchling's track
;(output) into the track of its
;permanent ancestor, in this case
;myrtle
]
;done with hatchling
]
;repeat until finished

END

```

#### turtleArt Thumbtack String Corkboard

This commented Logo source code creates a thumbtack, a cork board, and then draws random string art using them.

Try some of the primitives out in turtleSpaces interactive mode (the myrtle prompt) and see what they do!

You can drag-select the source code and then paste it into the turtleSpaces editor (which you enter by typing ed and Enter or pressing control-shift-E) using control-shift-V (paste)

Then exit back to interactive mode using control-shift-O (save) and then type stringart and Enter to execute it.

Change elements of the code and see what happens!

```TO tack
;create a thumbtack, or pushpin

setfillcolor pick without 5 without 10 range [1 15]
;pick a number between 1 and 15 except 5 and 10

cylinder 4 2 20
;cylinder takes width depth sides

lower 2
;lowers the turtle eg moves beneath it

cutcone 2 3 7 20
;cutcone takes topwidth bottomwidth depth sides

lo 7
;lo is shortcut for lower

cylinder 4 2 20
lo 2
setfc pick [5 10]
;setfc is shortcut for setfillcolor, the color
;used for painting shapes

cylinder 1 5 8
lo 5
cone 1 1 8
raise 16
;raises the turtle, eg moves above it
;all done!

END

TO corkboard
;create a corkboard to push our pins into

penup
setpos [-205 -116]

;setfillshade takes a range of -15 to 15

forward 5 lo 3 slideright 5
voxeloid 400 222 4
;voxeloid takes width height depth
;this creates the surface of our corkboard

slideleft 5 ra 3 back 5
setfs 6
; setfs is shortcut for setfillshade

voxeloid 10 232 10
;this and subsequent voxeloids
;create the frame

right 90
sl 10
;sl is shortcut for slideleft

voxeloid 10 410 10
fd 400
;fd is shortcut for forward

left 90
bk 10
;bk is shortcut for back

voxeloid 10 232 10
fd 222 lt 90 bk 10
;lt is shortcut for left

voxeloid 10 410 10
;that's all folks!

END

TO stringart
reset
;resets the workspace

snappy:run pick [
[pullout 10]
[pullout 30 orbitdown 70]
[orbitleft 20 orbitdown 45 rollright 10 pullout 60 rr 10 sl 25 lo 40]
;rr is shortcut for rollright
[orbitright 20 orbitdown 45 rollleft 10 pullout 60 rl 10 sr 25 lo 40]
;rl is shortcut for rollleft
]
;pick a camera sequence and execute it as
;snappy, the camera turtle

;if we need snappy to do more sophisticated
;things, we can store procedures inside him

;logo is all about having the freedom to do
;things in multiple ways!

setpenwidth 1 + random 5
;sets the 'width' of the pen, from 1 to 5

randps
randfs
;set a random shade between -12 and 12

penup
corkboard
;execute corkboard procedure

repeat 20 + random 20  [
;do the following 20 + 0-19 times:

randpc
;shortcut for randompencolor

setpos {-190 + random 380 -100 + random 200}
;move to a random position

pu
;pu is shortcut for penup

pushturtle
;save the turtle state on the 'stack'
;you can have multiple states on the stack

raise 10 + random 4 up -10 + random 20 rr -10 + random 20
;move into a semi-random position
;to give our tacks a more natural-looking
;placement

;moving in negative values moves the opposite
;direction, eg left -90 turns right 90 degrees

tack
;execute tack procedure
;(create a tack)

popturtle
;load the turtle state from the 'stack'
;this puts it back where and how it was when
;we pushed it

pendown
;pd is shortcut for pendown
;this will cause us to create a line to the
;next random position

]
;repeat the above however many times
;specified by 20 + random 20

hideturtle
;ta da!

;for extra credit, get some tacks, a corkboard, and some
;colored string and make some string art of your own!

;consider the angles the turtle would need to turn to travel
;along the line of string created between all the pins
;were the turtle to travel the string like driving