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 # What is ISSIE?
 
-* ISSIE is **a very easy-to-use schematic editor and simulator** for hierarchical design of **digital logic circuits**. Run it and see the built-in demos for what it can do! ISSIE is targeted at 1st year university students, but would be useful teaching in schools and even for quick hardware design and test in an industrial or research environment. For the latter use case although we allow Verilog input and output these features need a bit more work.
+* ISSIE is an **easy-to-use schematic editor and simulator** for hierarchical design of **digital logic circuits**. Run it and see the built-in demos for what it can do! ISSIE is targeted at 1st year university students, but would be useful teaching in schools and even for quick hardware design and test in an industrial or research environment. For the latter use case although we allow Verilog input and output these features need a bit more work.
 * ISSIE was motivated because we found that industry-standard CAD systems were too complex and buggy to be learnt in labs, and when learnt still nasty to use. Other educational products were too limited. We wanted **a schematic-based system to teach hierarchical design and digital electronics visually that would scale to large designs**.
 * ISSIE is an **open source project at Imperial College London developed over 5 years by students**. The code is cross-platform and binaries are released for Windows and Silicon (Arm64) Mac targets.
 * ISSIE is implemented using nearly 46K lines in the FP language F#, the equivalent of 150K lines in a typical OOP language. ISSIE's implementation is almost pure functional programming without assignment. This makes the codebase very maintainable! ISSIE has **its own digital simulator**, which uses **write-once semantics** on mutable arrays to be close to functional programming and also efficient.