The bind poses. The bind pose at each index refers to the bone with the same index.

The bind pose is the inverse of inverse transformation matrix of the bone, when the bone is in the bind pose.

	function Start () {
		gameObject.AddComponent(Animation);
		gameObject.AddComponent(SkinnedMeshRenderer);
		var renderer : SkinnedMeshRenderer = GetComponent(SkinnedMeshRenderer);
		// Build basic mesh
		var mesh : Mesh = new Mesh ();
		mesh.vertices = [Vector3(-1, 0, 0), Vector3(1, 0, 0), Vector3(-1, 5, 0),
						 Vector3(1, 5, 0)];
		mesh.uv = [Vector2(0, 0), Vector2(1, 0), Vector2(0, 1), Vector2(1, 1)];
		mesh.triangles = [0, 1, 2, 1, 3, 2];
		mesh.RecalculateNormals();
		// Assign mesh to mesh filter & renderer
		renderer.material = new Material (Shader.Find("Diffuse"));
		// Assign bone weights to mesh
		// We use 2 bones. One for the lower vertices, one for the upper vertices.
		var weights = new BoneWeight[4];
		weights[0].boneIndex0 = 0;
		weights[0].weight0 = 1;
		weights[1].boneIndex0 = 0;
		weights[1].weight0 = 1;
		weights[2].boneIndex0 = 1;
		weights[2].weight0 = 1;
		weights[3].boneIndex0 = 1;
		weights[3].weight0 = 1;
		mesh.boneWeights = weights;
		// Create Bone Transforms and Bind poses
		// One bone at the bottom and one at the top
		var bones : Transform[] = new Transform[2];
		var bindPoses : Matrix4x4[] = new Matrix4x4[2];
		bones[0] = new GameObject ("Lower").transform;
		bones[0].parent = transform;
		// Set the position relative to the parent
		bones[0].localRotation = Quaternion.identity;
		bones[0].localPosition = Vector3.zero;
		// The bind pose is bone's inverse transformation matrix
		// In this case the matrix we also make this matrix relative to the root
		// So that we can move the root game object around freely
		bindPoses[0] = bones[0].worldToLocalMatrix * transform.localToWorldMatrix;
		bones[1] = new GameObject ("Upper").transform;
		bones[1].parent = transform;
		// Set the position relative to the parent
		bones[1].localRotation = Quaternion.identity;
		bones[1].localPosition = Vector3 (0, 5, 0);
		// The bind pose is bone's inverse transformation matrix
		// In this case the matrix we also make this matrix relative to the root
		// So that we can move the root game object around freely
		bindPoses[1] = bones[1].worldToLocalMatrix * transform.localToWorldMatrix;
		mesh.bindposes = bindPoses;
		// Assign bones and bind poses
		renderer.bones = bones;
		renderer.sharedMesh = mesh;
		// Assign a simple waving animation to the bottom bone
		var curve : AnimationCurve = new AnimationCurve();
		curve.keys = [ new Keyframe (0, 0, 0, 0), new Keyframe (1, 3, 0, 0),
					   new Keyframe (2, 0.0, 0, 0) ];
		// Create the clip with the curve
		var clip : AnimationClip = new AnimationClip();
		clip.SetCurve("Lower", Transform, "m_LocalPosition.z", curve);
		// Add and play the clip
		animation.AddClip(clip, "test");
		animation.Play("test");
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Start() {
        gameObject.AddComponent<Animation>();
        gameObject.AddComponent<SkinnedMeshRenderer>();
        SkinnedMeshRenderer renderer = GetComponent<SkinnedMeshRenderer>();
        Mesh mesh = new Mesh();
        mesh.vertices = new Vector3[] {new Vector3(-1, 0, 0), new Vector3(1, 0, 0), new Vector3(-1, 5, 0), new Vector3(1, 5, 0)};
        mesh.uv = new Vector2[] {new Vector2(0, 0), new Vector2(1, 0), new Vector2(0, 1), new Vector2(1, 1)};
        mesh.triangles = new int[] {0, 1, 2, 1, 3, 2};
        mesh.RecalculateNormals();
        renderer.material = new Material(Shader.Find("Diffuse"));
        BoneWeight[] weights = new BoneWeight[4];
        weights[0].boneIndex0 = 0;
        weights[0].weight0 = 1;
        weights[1].boneIndex0 = 0;
        weights[1].weight0 = 1;
        weights[2].boneIndex0 = 1;
        weights[2].weight0 = 1;
        weights[3].boneIndex0 = 1;
        weights[3].weight0 = 1;
        mesh.boneWeights = weights;
        Transform[] bones = new Transform[2];
        Matrix4x4[] bindPoses = new Matrix4x4[2];
        bones[0] = new GameObject("Lower").transform;
        bones[0].parent = transform;
        bones[0].localRotation = Quaternion.identity;
        bones[0].localPosition = Vector3.zero;
        bindPoses[0] = bones[0].worldToLocalMatrix * transform.localToWorldMatrix;
        bones[1] = new GameObject("Upper").transform;
        bones[1].parent = transform;
        bones[1].localRotation = Quaternion.identity;
        bones[1].localPosition = new Vector3(0, 5, 0);
        bindPoses[1] = bones[1].worldToLocalMatrix * transform.localToWorldMatrix;
        mesh.bindposes = bindPoses;
        renderer.bones = bones;
        renderer.sharedMesh = mesh;
        AnimationCurve curve = new AnimationCurve();
        curve.keys = new Keyframe[] {new Keyframe(0, 0, 0, 0), new Keyframe(1, 3, 0, 0), new Keyframe(2, 0.0F, 0, 0)};
        AnimationClip clip = new AnimationClip();
        clip.SetCurve("Lower", typeof(Transform), "m_LocalPosition.z", curve);
        animation.AddClip(clip, "test");
        animation.Play("test");
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Start() as void:
		gameObject.AddComponent[of Animation]()
		gameObject.AddComponent[of SkinnedMeshRenderer]()
		renderer as SkinnedMeshRenderer = GetComponent[of SkinnedMeshRenderer]()
		mesh as Mesh = Mesh()
		mesh.vertices = (of Vector3: Vector3(-1, 0, 0), Vector3(1, 0, 0), Vector3(-1, 5, 0), Vector3(1, 5, 0))
		mesh.uv = (of Vector2: Vector2(0, 0), Vector2(1, 0), Vector2(0, 1), Vector2(1, 1))
		mesh.triangles = (of int: 0, 1, 2, 1, 3, 2)
		mesh.RecalculateNormals()
		renderer.material = Material(Shader.Find('Diffuse'))
		weights as (BoneWeight) = array[of BoneWeight](4)
		weights[0].boneIndex0 = 0
		weights[0].weight0 = 1
		weights[1].boneIndex0 = 0
		weights[1].weight0 = 1
		weights[2].boneIndex0 = 1
		weights[2].weight0 = 1
		weights[3].boneIndex0 = 1
		weights[3].weight0 = 1
		mesh.boneWeights = weights
		bones as (Transform) = array[of Transform](2)
		bindPoses as (Matrix4x4) = array[of Matrix4x4](2)
		bones[0] = GameObject('Lower').transform
		bones[0].parent = transform
		bones[0].localRotation = Quaternion.identity
		bones[0].localPosition = Vector3.zero
		bindPoses[0] = (bones[0].worldToLocalMatrix * transform.localToWorldMatrix)
		bones[1] = GameObject('Upper').transform
		bones[1].parent = transform
		bones[1].localRotation = Quaternion.identity
		bones[1].localPosition = Vector3(0, 5, 0)
		bindPoses[1] = (bones[1].worldToLocalMatrix * transform.localToWorldMatrix)
		mesh.bindposes = bindPoses
		renderer.bones = bones
		renderer.sharedMesh = mesh
		curve as AnimationCurve = AnimationCurve()
		curve.keys = (of Keyframe: Keyframe(0, 0, 0, 0), Keyframe(1, 3, 0, 0), Keyframe(2, 0.0F, 0, 0))
		clip as AnimationClip = AnimationClip()
		clip.SetCurve('Lower', typeof(Transform), 'm_LocalPosition.z', curve)
		animation.AddClip(clip, 'test')
		animation.Play('test')