We present a new simple Internet of Things (IoT) device that we call “Smart Bottle Cap”, which enables a standard bottle to become a user-controllable liquid pouring system. It consists of a mini vacuum pump to start the liquid flowing, a microcontroller to control the liquid flow, a BLE module to connect it to a smartphone, an accelerometer to detect the tilt angle of the bottle, an LED for drawing the attention of users, and a 3.7 V LiPo battery. The device's novel point is that a flow control mechanism built into a standard bottle cap makes the system suitable for general use and enables it to be easily extended.

A process of mixing viscous fluids, such as oil-based paints is applied to generate marble patterns. It is difficult to get the exact flow function of the viscous fluid, then we express the flow in terms of velocity vectors derived from simplified flow phenomena, in which the viscous liquid is supposed to be a collection of finite liquid elements. The position change of each element is calculated as the function of time and several examples of the obtained marble patterns are illustrated.