Hi!
The Hacktoberfest - an event where you can contribute to any open source or available for PRs project and get awesome rewards! - is coming and I would like to here from you, if you are planning any contributions and if so, it would be great to share them here when they are out! 
P.S. The T-shirt from last year is still cool!
I always try to participate!
In previous years we’ve seen people contribute to the Defold documentation (translations) as part of Hacktoberfest. I also hope we can get some contributions for a couple of our official Defold extensions:
I’d also love to see the community contribute more examples for the Examples section of the Learn page. It would be really cool to have examples of more or less all of the Defold API functions.
Agreed! I think I have t-shirts from the last three or four years!
This is a very cool idea!
At first I created a very simple example with hinge joints - a cart! 
Everything is already published here:
@britzl I hope you could still add defold/examples as a participating project?
Thanks for the example. I am wondering why the joint has to be destroyed and recreated when changing directions?
This is probably a bug that I’m currently investigating. It should not be requried.
Yes, I will update the example as soon as set will affect a currently created joint 
It actually does work. Here’s from the example I shared earlier on Discord:
local FRONTWHEEL = "frontwheel#collisionobject"
local BACKWHEEL = "backwheel#collisionobject"
local BODY = "body#collisionobject"
local FRONT_ID = hash("frontwheel")
local BACK_ID = hash("backwheel")
local V3ZERO = vmath.vector3(0)
function init(self)
local props = {
motor_speed = 20,
enable_limit = false,
enable_motor = true,
max_motor_torque = 100,
}
physics.create_joint(physics.JOINT_TYPE_HINGE, FRONTWHEEL, FRONT_ID, V3ZERO, BODY, vmath.vector3(40, -10, 0), props)
physics.create_joint(physics.JOINT_TYPE_HINGE, BACKWHEEL, BACK_ID, V3ZERO, BODY, vmath.vector3(-40, -10, 0), props)
timer.delay(2, false, function()
local props = {
motor_speed = -20,
enable_limit = false,
enable_motor = true,
max_motor_torque = 100,
}
physics.set_joint_properties(FRONTWHEEL, FRONT_ID, props)
physics.set_joint_properties(BACKWHEEL, BACK_ID, props)
end)
end
The problem was that I had the motor torque set too low and the initial speed too high. With a higher torque the direction of movement changes as expected.
Thank you so much! I checked it and it works as expected, a great lesson I made a PR with improvements 
As a second task for this Hacktoberfest I continue translating Defold manuals, this time message passing (though it is still not visible on the Defold website)
Ah, approved but not merged! It will be available soon!
@Pawel Inspired by this post and your great Joint Physics example, I decided to give it a go and submitted an example on panning sound. Now the example is up on the site. 
cheers~
A great example @MasterMind! Perfectly shows the usage of panning
I made two further challenges:
I continue translating docs to Polish, made a PR with translations of importing assets, graphics and models
Also I created another example! It’s in verification now and it’s about animating cursor value of the sprite:
Hmm, the gif recorder is way lower than 60 FPS
Edit: But it’s live now, you can check it out
Any ideas for further examples?
Perhaps examples of other joint types?
Here it is!
Fixed joint for rope simulation and spring joint for resilient rope simulation
And additionally a changing gravity!
PR is pending so, soon it iwll be on the website