I think it is very nicely done, graphically.
You seem to be saying that our shadow shows that there is the sun. And, like this, our thoughts show there is more than us.
I would say that our thoughts can be what God is saying in us . . . or what Satan is saying. So, it is important to know who is broadcasting into us.
And Hebrews 4:12 says,
"For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart." (Hebrews 4:12)
So, God's light of His word does not only cast a shadow, but discerns who the shadow belongs to. And in His thoughts we have light and His kind and gentle and caring Spirit. But in what are not His thoughts, there is what darkens us with worry and depression and frustration and bitterness and drives and distraction of lusts.
So, it is good to have thoughts in God's peace which "will guard your hearts and minds through Christ Jesus." (in Philippians 4:6-8)