A code example for a Rigid body suspended from a spring constraint!

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Nature2D = require(ReplicatedStorage.Nature2D)

local Engine = Nature2D.init(SomeScreenGuiInstance)
Engine:CreateCanvas(Vector2.new(0, 0), Vector2.new(1920, 1080), SomeCanvasFrame)
Engine:SetPhysicalProperty("AirFriction", 0.02)

local Anchor = Engine:Create("Point", {
		Position = workspace.CurrentCamera.ViewportSize * Vector2.new(0.5, 0)
    Snap = true
})

local Box = Engine:Create("RigidBody", {
		Mass = 1,
		Object = SomeGuiObject,
		Collidable = true,
		Anchored = false
})

local Spring = Engine:Create("Constraint", {
		Type = "Spring",
		Point1 = Anchor,
		Point2 = Box:GetVertices()[1],
		Visible = true
})

Engine:Start()