Thoughts grow exponentially. With each additional thought you think about a particular topic, you begin to vibrate in harmony with its vibration to a greater degree. Thus, each time you think another matching thought, it becomes easier and easier for your vibration to become a match to this thought's vibration and thus you become a better match to it at a faster and faster rate as a result.
This increase in harmony is made apparent in the form of additional thoughts that are harmonized with the vibration of the initial thought to a greater degree. For example, when you first think a thought, it may seem to be very isolated and singular within your mind, small in nature, the vibration itself only filling a small part of your mind and body, but as you continue to think matching thoughts, the vibration becomes more expansive and thus fills your body and your environment to a greater degree which in turn allows you to develop more comprehensive thoughts that match the vibration being harmonized with to an even greater degree.
This increased harmony of thought comes in the form of you thinking about the vibration permeating your environment to a greater extent as you continue to harmonize with the vibration thus making the initial thought a reality within your mind, as it was when you first thought it, but also a reality within the exterior world to a degree which is equal to the extent you gave thoughts matching the initial vibration your attention. Exponential growth in this sense also occurs within the mind in the form of gaining additional knowledge, access to information about a topic, that is equal in nature to the extent to which you have given the topic your attention.