In a block diagram, signal flow is represented by the wires that connect one block to another. The triangular tab connectors on the blocks indicate the direction of signal flow. Scalar signals are represented as thin wires; vector and matrix signals are represented as thick wires.
You can also transmit signals using variables. A variable lets you name and transmit a signal throughout a block diagram without using wires. Typically, you use a variable block for system-wide variables or signals that would be laborious or visually messy to represent as wires. For more information, see Using variables to transmit signals.
You can manually bundle and unbundle signals using the scalarToVec and vecToScalar blocks.