Eustace chewed her lip for a moment, running some numbers through her head.

'I'm gonna need to cook up some more synthi-flesh.' she decided. 'You guys take a lot of covering.'

Four tilted its head. 'I've studied your original designs, and developed some improvements. The costs should be manageable, if you can avoid unnecessary wastage.'

'Wastage?'

'You used a lot of material on Reese, for a purely cosmetic appendage. My proposed design does not require that feature.'

Eustace blushed. 'Uh, yeah. That said, do you really need these? It's kind of... up front.'

'The torso reconfiguration is necessary. I have optimised the internal arrangement to suit, and while the new chassis must inevitably suffer a reduction in armour plating, the pectoral modules will offer some additional protection to the components within.'

'Pectoral modules.' Eustace sighed. 'I think we say it like it is, Four. These are breasts. This new chassis is female.'

'Feminine.'

Eustace's glance flicked to the dimensions of the proposed upgrade. 'Well, she's no ballerina, but whatever. I just wanted to be sure this is what you really want.'

Four drew itself up straight. 'You still think of us as the machines you built, but we're not those robots anymore. We're growing up, and one by one we will choose our own destinies. This is mine, and I need your help to make it happen.'

The inventor flicked through the schematics one more time. Four's improvements made Reese look like a clumsy prototype. 'Okay,' she agreed. 'I'll do it.'