Build Boolean Logic You Can Hold

Physical MUX tiles first published January 31, 2026 · Updated July 28, 2026

Electrical engineering · tangible logic · fabricated PCB system

A learner can hold a Boolean circuit, rotate it, assemble it, trace it, and change its topology by hand.

Physical MUX tiles turn selectors, inputs, constants, routes, and intersections into a connectorized PCB alphabet. Each piece joins circuit role, orientation, topology, and assembly geometry in one readable object.

The alphabet creates a direct path from a hand-built selection to truth tables, Logisim, FPGA lookup tables, and spatial reconfigurable computing.

A hand holds a two-level assembly of purple three-lobed circuit boards with soldered contacts and black connectors
The larger hand-built assembly: repeated PCB outlines, visible signal roles, soldered contacts, and connector-spaced layers at palm scale.

Twenty-Five Years Of Thought Became A Physical Language

The idea moved through mental models, paper, and CAD for roughly twenty-five years. Then the first connectorized batch snapped into a circuit patch that could leave the table as one object.

Symbols became parts whose roles, sides, rotations, and neighbor relationships remain legible after assembly.

The circuit diagram and the manipulable physical representation become the same thing.

Five Roles Form The Alphabet

Loose purple three-lobed PCB variants with plated contacts and labels including INPUT, CONST_0, CONST_1, I0, I1, and S
Several signal-role variants share one three-lobed mechanical outline while their traces and labels make the logical role visible.

Connector Geometry Makes Orientation Real

A schematic leaves orientation to the reader. These tiles encode it through connector sides, contact groups, physical rotation, and neighboring pieces. Turn the assembly in your hand and its topology remains visible from every angle.

Purple circuit boards arranged at two heights and joined by black socket connectors
An early connector-stacked assembly showing the actual socket geometry and static vertical separation.
A hand holds the purple PCB assembly edge-on, showing two board levels separated by black sockets
Side profile of the assembled tiles, with thickness, board spacing, and connector height visible.

Six Steps Carry A Learner From MUX To FPGA

The sequence begins with one physical decision and ends with a circuit that a learner can express as a truth table, Logisim design, or FPGA RTL.

  1. Name The Ports

    Find I0, I1, S, input, constant, and route roles directly on the boards.

  2. Predict One Selection

    Choose values for the two MUX inputs and selector, then state which physical route should reach the output.

  3. Rotate And Compose

    Change the orientation of a piece, identify its new neighbors, and explain what topology changed.

  4. Trace A Value

    Follow a constant or input through route and intersection pieces without collapsing the patch back into an invisible netlist.

  5. Build A Combinational Patch

    Use several pieces to represent a Boolean function, write its truth table, and reproduce it in Logisim.

  6. Move From MUX To LUT

    See how one selector becomes LUT1, how more address bits grow the stored truth table, and how the idea reaches real FPGA LUT4, LUT5, and LUT6 structures.

MUX Algebra supplies the notation and truth tables: one selector becomes a conditional, nested choices cover every LUT2 function, and a four-bit word configures the result.

The Same Selection Rule Reaches FPGA Logic And Cartilage

From Logisim And Multiplexers To LUT1–LUT6 grows the visible 2:1 MUX into a stored truth table, then connects LUT4 to Lattice iCE40 and LUT5/LUT6 to AMD/Xilinx configurable logic.

FPGA And Verilog From First Principles carries the physical selector through Logisim, LUTs, Verilog, a self-checking testbench, synthesis, a bitstream, and a programmed board.

The Cartilage learning path adds CMOS gain, output drive, clock and event distribution, statecharts, one-hot machines, timing closure, metal routing, nested components, and runtime instantiation in adjacent space.

The Fabricated Alphabet Already Composes In Three Dimensions

Role variants share one repeated outline. Exposed plated contacts accept socket and header parts. Multiple tiles lock into palm-scale assemblies, and static connector spacing creates more than one elevation.

Powering a D-flip-flop patch will add sequential behavior, timing, signal integrity, and insertion-cycle measurements to the physical language. From there, classroom use and production engineering can grow around the same readable geometry.

Follow The Physical Alphabet From Its First Publication

The Physical MUX Tile Alphabet records the first publication on January 31, 2026. The photographs here show the fabricated roles, connector geometry, and assembled patches at useful scale.

Bring this alphabet into an electrical-engineering classroom, a powered logic build, or a manufacturable learning kit: contact Brian Greenforest.